0001692115-22-000024 | 10-Q | XBRL Viewer | Southwest GAS Holdings INC

Cover - shares	6 Months Ended
Cover - shares	Jun. 30, 2022	Jul. 29, 2022
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity File Number	001-37976
Entity Registrant Name	Southwest Gas Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3881866
Entity Address, Address Line One	8360 S. Durango Drive
Entity Address, Address Line Two	Post Office Box 98510
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89193-8510
City Area Code	(702)
Local Phone Number	876-7237
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		67,007,222
Entity Central Index Key	0001692115
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Southwest Gas Holdings, Inc. Common Stock, $1 Par Value
Entity Information [Line Items]
Title of 12(b) Security	Southwest Gas Holdings, Inc. Common Stock, $1 Par Value
Trading Symbol	SWX
Security Exchange Name	NYSE
Preferred Stock Purchase Rights
Entity Information [Line Items]
Title of 12(b) Security	Preferred Stock Purchase Rights
Security Exchange Name	NYSE
No Trading Symbol Flag	true
Southwest Gas Corporation
Entity Information [Line Items]
Document Type	10-Q
Entity File Number	1-7850
Entity Registrant Name	Southwest Gas Corporation
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	88-0085720
Entity Address, Address Line One	8360 S. Durango Drive
Entity Address, Address Line Two	Post Office Box 98510
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89193-8510
City Area Code	(702)
Local Phone Number	876-7237
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Central Index Key	0000092416
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Regulated operations plant:
Gas plant	$ 11,049,050	$ 10,789,690
Less: accumulated depreciation	(3,496,191)	(3,397,736)
Construction work in progress	218,638	202,068
Net regulated operations plant	7,771,497	7,594,022
Other property and investments, net	1,312,701	1,316,479
Current assets:
Cash and cash equivalents	215,963	222,697
Accounts receivable, net of allowance	750,794	707,127
Accrued utility revenue	40,000	84,900
Income taxes receivable, net	19,147	16,816
Deferred purchased gas costs	354,571	291,145
Prepaid and other current assets	263,363	292,082
Total current assets	1,643,838	1,614,767
Noncurrent assets:
Goodwill	1,750,472	1,781,332
Deferred income taxes	168	121
Deferred charges and other assets	444,332	458,536
Total noncurrent assets	2,194,972	2,239,989
Total assets	12,923,008	12,765,257
Capitalization:
Common stock, $1 par (authorized - 120,000,000 shares; issued and outstanding - 67,003,792 and 60,422,081 shares)	68,634	62,052
Additional paid-in capital	2,279,493	1,824,216
Accumulated other comprehensive loss, net	(45,528)	(46,761)
Retained earnings	1,156,253	1,114,313
Total equity	3,458,852	2,953,820
Redeemable noncontrolling interests	122,656	196,717
Long-term debt, less current maturities	4,588,454	4,115,684
Total capitalization	8,169,962	7,266,221
Current liabilities:
Current maturities of long-term debt	41,276	297,324
Short-term debt	1,462,747	1,909,000
Accounts payable	306,753	353,365
Customer deposits	53,991	59,327
Income taxes payable, net	1,725	6,734
Accrued general taxes	55,883	53,473
Accrued interest	35,697	30,964
Deferred purchased gas costs	4,986	5,736
Other current liabilities	387,359	396,126
Total current liabilities	2,350,417	3,112,049
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	785,258	768,868
Accumulated removal costs	494,554	480,583
Other deferred credits and other long-term liabilities	1,122,817	1,137,536
Total deferred income taxes and other credits	2,402,629	2,386,987
Total capitalization and liabilities	$ 12,923,008	$ 12,765,257

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common stock, par (in USD per share)	$ 1	$ 1
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	67,003,792	60,422,081
Common stock, outstanding (in shares)	67,003,792	60,422,081

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating revenues:
Regulated operations revenues	$ 440,030	$ 292,796	$ 1,183,562	$ 814,728	$ 1,890,624	$ 1,400,052
Utility infrastructure services revenues	706,090	528,625	1,229,967	892,600	2,496,028	2,012,582
Total operating revenues	1,146,120	821,421	2,413,529	1,707,328	4,386,652	3,412,634
Operating expenses:
Net cost of gas sold	147,860	76,496	446,778	232,517	645,168	347,060
Operations and maintenance	175,791	104,833	325,094	211,523	586,717	416,439
Depreciation and amortization	108,010	82,848	230,656	176,290	425,407	343,447
Taxes other than income taxes	22,606	19,338	47,422	40,025	87,740	71,765
Utility infrastructure services expenses	646,193	478,640	1,149,425	814,254	2,290,638	1,794,145
Total operating expenses	1,100,460	762,155	2,199,375	1,474,609	4,035,670	2,972,856
Operating income	45,660	59,266	214,154	232,719	350,982	439,778
Other income and (expenses):
Net interest deductions	(53,206)	(25,939)	(101,569)	(49,903)	(170,864)	(106,550)
Other income (deductions)	(2,835)	(1,311)	(1,591)	(863)	(4,227)	5,193
Total other income and (expenses)	(56,041)	(27,250)	(103,160)	(50,766)	(175,091)	(101,357)
Income (loss) before income taxes	(10,381)	32,016	110,994	181,953	175,891	338,421
Income tax expense (benefit)	(4,300)	5,542	19,825	36,634	22,839	67,003
Net income (loss)	(6,081)	26,474	91,169	145,319	153,052	271,418
Net income attributable to noncontrolling interests	494	1,355	1,566	2,907	5,082	7,189
Net income (loss) attributable to Southwest Gas Holdings, Inc.	$ (6,575)	$ 25,119	$ 89,603	$ 142,412	$ 147,970	$ 264,229
Earnings (loss) per share:
Basic (in USD per share)	$ (0.10)	$ 0.43	$ 1.40	$ 2.45	$ 2.39	$ 4.61
Diluted (in USD per share)	$ (0.10)	$ 0.43	$ 1.40	$ 2.45	$ 2.38	$ 4.60
Weighted average shares:
Basic (in shares)	67,045	58,607	63,909	58,106	62,022	57,348
Diluted (in shares)	67,190	58,710	64,041	58,197	62,157	57,440

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (6,081)	$ 26,474	$ 91,169	$ 145,319	$ 153,052	$ 271,418
Defined benefit pension plans:
Net actuarial gain (loss)	0	0	0	0	44,974	(43,730)
Amortization of prior service cost	33	182	66	364	431	802
Amortization of net actuarial loss	6,615	8,472	13,231	16,946	30,179	31,322
Regulatory adjustment	(5,524)	(7,277)	(11,047)	(14,554)	(63,520)	3,856
Net defined benefit pension plans	1,124	1,377	2,250	2,756	12,064	(7,750)
Forward-starting interest rate swaps (“FSIRS”):
Amounts reclassified into net income	0	414	416	827	1,241	2,023
Net forward-starting interest rate swaps	0	414	416	827	1,241	2,023
Foreign currency translation adjustments	(2,680)	909	(1,433)	1,732	(3,145)	5,656
Total other comprehensive income (loss), net of tax	(1,556)	2,700	1,233	5,315	10,160	(71)
Comprehensive income (loss)	(7,637)	29,174	92,402	150,634	163,212	271,347
Comprehensive income attributable to noncontrolling interests	494	1,355	1,566	2,907	5,082	7,189
Comprehensive income (loss) attributable to Southwest Gas Holdings, Inc.	$ (8,131)	$ 27,819	$ 90,836	$ 147,727	$ 158,130	$ 264,158

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 91,169	$ 145,319	$ 153,052	$ 271,418
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	230,656	176,290	425,407	343,447
Deferred income taxes	30,163	44,178	47,197	63,774
Changes in current assets and liabilities:
Accounts receivable, net of allowances	(42,212)	10,005	(103,771)	(29,021)
Accrued utility revenue	44,900	43,900	(1,500)	(2,700)
Deferred purchased gas costs	(64,176)	(287,687)	(120,217)	(305,043)
Accounts payable	(33,356)	(41,075)	58,145	(1,571)
Accrued taxes	(5,023)	(3,164)	(8,584)	2,988
Other current assets and liabilities	16,480	(31,928)	(40,801)	(3,039)
Gains on sale of property and equipment	(3,475)	(4,033)	(6,348)	(5,572)
Changes in undistributed stock compensation	7,036	5,736	10,594	8,518
Equity AFUDC	(575)	0	(575)	(2,543)
Changes in deferred charges and other assets	13,736	(11,171)	11,366	(35,494)
Changes in other liabilities and deferred credits	(21,705)	(45,013)	(50,321)	(52,865)
Net cash provided by operating activities	263,618	1,357	373,644	252,297
CASH FLOW FROM INVESTING ACTIVITIES:
Construction expenditures and property additions	(367,932)	(338,049)	(745,509)	(739,719)
Acquisition of businesses, net of cash acquired	(18,809)	0	(2,373,069)	0
Changes in customer advances	17,051	7,507	25,518	17,442
Other	3,905	9,159	13,002	13,367
Net cash used in investing activities	(365,785)	(321,383)	(3,080,058)	(708,910)
CASH FLOW FROM FINANCING ACTIVITIES:
Issuance of common stock, net	456,280	121,302	548,619	205,049
Centuri distribution to redeemable noncontrolling interest	(39,649)	0	(39,649)	0
Dividends paid	(77,419)	(67,130)	(148,511)	(131,189)
Issuance of long-term debt, net	759,602	82,245	2,338,053	124,319
Retirement of long-term debt	(412,263)	(60,500)	(804,427)	(299,370)
Change in credit facility and commercial paper	(130,000)	0	(150,000)	150,000
Change in short-term debt	(446,253)	211,000	(705,253)	260,000
Issuance of short-term debt	0	0	1,850,000	0
Withholding remittance - share-based compensation	(2,089)	(1,243)	(2,110)	(1,243)
Other	(12,811)	(1,623)	(11,917)	(3,565)
Net cash provided by financing activities	95,398	284,051	2,874,805	304,001
Effects of currency translation on cash and cash equivalents	35	188	7	586
Change in cash and cash equivalents	(6,734)	(35,787)	168,398	(152,026)
Cash and cash equivalents at beginning of period	222,697	83,352	47,565	199,591
Cash and cash equivalents at end of period	215,963	47,565	215,963	47,565
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	92,297	47,475	149,174	101,227
Income taxes paid (received), net	$ 8,300	$ 6,659	$ 5,849	$ 15,118

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common stock shares	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings	Southwest Gas Holdings, Inc.
Beginning balance (in shares) at Dec. 31, 2020		57,193,000
Beginning balance at Dec. 31, 2020		$ 58,823	$ 1,609,155	$ (61,003)	$ 1,067,978
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuances (in shares)		1,895,000
Common stock issuances		$ 1,895	124,417
Foreign currency exchange translation adjustment				1,732
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax				2,756
FSIRS amounts reclassified to net income, net of tax	$ 827			827
Net income (loss)					142,412
Dividends declared					(70,205)
Redemption value adjustments					(31,906)
Ending balance (in shares) at Jun. 30, 2021		59,088,000
Ending balance at Jun. 30, 2021		$ 60,718	1,733,572	(55,688)	1,108,279	$ 2,846,881
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in USD per share)	$ 1.19
Beginning balance (in shares) at Mar. 31, 2021		57,995,000
Beginning balance at Mar. 31, 2021		$ 59,625	1,660,108	(58,388)	1,112,377
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuances (in shares)		1,093,000
Common stock issuances		$ 1,093	73,464
Foreign currency exchange translation adjustment				909
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax				1,377
FSIRS amounts reclassified to net income, net of tax	$ 414			414
Net income (loss)					25,119
Dividends declared					(35,329)
Redemption value adjustments					6,112
Ending balance (in shares) at Jun. 30, 2021		59,088,000
Ending balance at Jun. 30, 2021		$ 60,718	1,733,572	(55,688)	1,108,279	2,846,881
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in USD per share)	$ 0.595
FSIRS amounts reclassified to net income, net of tax	$ 1,241
Ending balance (in shares) at Jun. 30, 2022	67,003,792	67,004,000
Ending balance at Jun. 30, 2022		$ 68,634	2,279,493	(45,528)	1,156,253	3,458,852
Beginning balance (in shares) at Dec. 31, 2021	60,422,081	60,422,000
Beginning balance at Dec. 31, 2021		$ 62,052	1,824,216	(46,761)	1,114,313
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuances (in shares)		6,582,000
Common stock issuances		$ 6,582	455,277
Foreign currency exchange translation adjustment				(1,433)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax				2,250
FSIRS amounts reclassified to net income, net of tax	$ 416			416
Net income (loss)					89,603
Dividends declared					(83,641)
Redemption value adjustments	$ (35,978)				35,978
Ending balance (in shares) at Jun. 30, 2022	67,003,792	67,004,000
Ending balance at Jun. 30, 2022		$ 68,634	2,279,493	(45,528)	1,156,253	3,458,852
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in USD per share)	$ 1.24
Beginning balance (in shares) at Mar. 31, 2022		66,849,000
Beginning balance at Mar. 31, 2022		$ 68,479	2,273,837	(43,972)	1,190,738
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuances (in shares)		155,000
Common stock issuances		$ 155	5,656
Foreign currency exchange translation adjustment				(2,680)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax				1,124
FSIRS amounts reclassified to net income, net of tax	$ 0			0
Net income (loss)					(6,575)
Dividends declared					(41,732)
Redemption value adjustments					13,822
Ending balance (in shares) at Jun. 30, 2022	67,003,792	67,004,000
Ending balance at Jun. 30, 2022		$ 68,634	$ 2,279,493	$ (45,528)	$ 1,156,253	$ 3,458,852
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in USD per share)	$ 0.62

CONDENSED CONSOLIDATED BALANCE SHEETS - Southwest - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
ASSETS
Gas plant	$ 11,049,050	$ 10,789,690
Less: accumulated depreciation	(3,496,191)	(3,397,736)
Construction work in progress	218,638	202,068
Net regulated operations plant	7,771,497	7,594,022
Other property and investments, net	1,312,701	1,316,479
Current assets:
Cash and cash equivalents	215,963	222,697
Accounts receivable, net of allowance	750,794	707,127
Accrued utility revenue	40,000	84,900
Income taxes receivable, net	19,147	16,816
Deferred purchased gas costs	354,571	291,145
Prepaid and other current assets	263,363	292,082
Total current assets	1,643,838	1,614,767
Noncurrent assets:
Goodwill	1,750,472	1,781,332
Deferred charges and other assets	444,332	458,536
Total noncurrent assets	2,194,972	2,239,989
Total assets	12,923,008	12,765,257
Capitalization:
Common stock	68,634	62,052
Additional paid-in capital	2,279,493	1,824,216
Accumulated other comprehensive loss, net	(45,528)	(46,761)
Retained earnings	1,156,253	1,114,313
Total equity	3,458,852	2,953,820
Long-term debt, less current maturities	4,588,454	4,115,684
Total capitalization	8,169,962	7,266,221
Current liabilities:
Current maturities of long-term debt	41,276	297,324
Short-term debt	1,462,747	1,909,000
Accounts payable	306,753	353,365
Customer deposits	53,991	59,327
Accrued general taxes	55,883	53,473
Accrued interest	35,697	30,964
Other current liabilities	387,359	396,126
Total current liabilities	2,350,417	3,112,049
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	785,258	768,868
Accumulated removal costs	494,554	480,583
Other deferred credits and other long-term liabilities	1,122,817	1,137,536
Total deferred income taxes and other credits	2,402,629	2,386,987
Total capitalization and liabilities	12,923,008	12,765,257
Southwest Gas Corporation
ASSETS
Gas plant	9,137,313	8,901,575
Less: accumulated depreciation	(2,613,096)	(2,538,508)
Construction work in progress	193,269	183,485
Net regulated operations plant	6,717,486	6,546,552
Other property and investments, net	146,599	153,093
Current assets:
Cash and cash equivalents	102,143	38,691
Accounts receivable, net of allowance	141,820	169,666
Accrued utility revenue	40,000	84,900
Income taxes receivable, net	6,665	7,826
Deferred purchased gas costs	354,571	291,145
Receivable from parent	0	1,031
Prepaid and other current assets	207,545	242,243
Total current assets	852,744	835,502
Noncurrent assets:
Goodwill	10,095	10,095
Deferred charges and other assets	388,054	405,021
Total noncurrent assets	398,149	415,116
Total assets	8,114,978	7,950,263
Capitalization:
Common stock	49,112	49,112
Additional paid-in capital	1,622,006	1,618,911
Accumulated other comprehensive loss, net	(44,247)	(46,913)
Retained earnings	952,725	906,827
Total equity	2,579,596	2,527,937
Long-term debt, less current maturities	2,904,099	2,440,603
Total capitalization	5,483,695	4,968,540
Current liabilities:
Current maturities of long-term debt	0	275,000
Short-term debt	225,000	250,000
Accounts payable	143,569	234,070
Customer deposits	50,925	56,127
Accrued general taxes	51,722	53,064
Accrued interest	26,942	22,926
Payable to parent	330	0
Other current liabilities	162,151	146,422
Total current liabilities	660,639	1,037,609
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	676,294	638,828
Accumulated removal costs	437,000	424,000
Other deferred credits and other long-term liabilities	857,350	881,286
Total deferred income taxes and other credits	1,970,644	1,944,114
Total capitalization and liabilities	$ 8,114,978	$ 7,950,263

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Regulated operations revenues	$ 440,030	$ 292,796	$ 1,183,562	$ 814,728	$ 1,890,624	$ 1,400,052
Operating expenses:
Net cost of gas sold	147,860	76,496	446,778	232,517	645,168	347,060
Operations and maintenance	175,791	104,833	325,094	211,523	586,717	416,439
Depreciation and amortization	108,010	82,848	230,656	176,290	425,407	343,447
Taxes other than income taxes	22,606	19,338	47,422	40,025	87,740	71,765
Total operating expenses	1,100,460	762,155	2,199,375	1,474,609	4,035,670	2,972,856
Operating income	45,660	59,266	214,154	232,719	350,982	439,778
Other income and (expenses):
Net interest deductions	(53,206)	(25,939)	(101,569)	(49,903)	(170,864)	(106,550)
Other income (deductions)	(2,835)	(1,311)	(1,591)	(863)	(4,227)	5,193
Total other income and (expenses)	(56,041)	(27,250)	(103,160)	(50,766)	(175,091)	(101,357)
Income (loss) before income taxes	(10,381)	32,016	110,994	181,953	175,891	338,421
Income tax expense (benefit)	(4,300)	5,542	19,825	36,634	22,839	67,003
Net income (loss) attributable to Southwest Gas Holdings, Inc.	(6,575)	25,119	89,603	142,412	147,970	264,229
Southwest Gas Corporation
Regulated operations revenues	377,942	292,796	1,054,481	814,728	1,761,543	1,400,052
Operating expenses:
Net cost of gas sold	146,654	76,496	443,775	232,517	642,165	347,060
Operations and maintenance	127,811	103,137	247,447	209,272	476,725	413,246
Depreciation and amortization	55,930	57,631	128,044	126,329	255,113	243,701
Taxes other than income taxes	20,098	19,338	41,750	40,025	82,068	71,765
Total operating expenses	350,493	256,602	861,016	608,143	1,456,071	1,075,772
Operating income	27,449	36,194	193,465	206,585	305,472	324,280
Other income and (expenses):
Net interest deductions	(28,633)	(24,175)	(55,243)	(46,341)	(106,462)	(98,440)
Other income (deductions)	(3,433)	(1,165)	(2,118)	(615)	(6,062)	5,493
Total other income and (expenses)	(32,066)	(25,340)	(57,361)	(46,956)	(112,524)	(92,947)
Income (loss) before income taxes	(4,617)	10,854	136,104	159,629	192,948	231,333
Income tax expense (benefit)	(2,351)	(559)	26,575	29,501	26,412	37,628
Net income (loss) attributable to Southwest Gas Holdings, Inc.	$ (2,266)	$ 11,413	$ 109,529	$ 130,128	$ 166,536	$ 193,705

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net income (loss)	$ (6,081)	$ 26,474	$ 91,169	$ 145,319	$ 153,052	$ 271,418
Defined benefit pension plans:
Net actuarial gain (loss)	0	0	0	0	44,974	(43,730)
Amortization of prior service cost	33	182	66	364	431	802
Amortization of net actuarial loss	6,615	8,472	13,231	16,946	30,179	31,322
Regulatory adjustment	(5,524)	(7,277)	(11,047)	(14,554)	(63,520)	3,856
Net defined benefit pension plans	1,124	1,377	2,250	2,756	12,064	(7,750)
Forward-starting interest rate swaps (“FSIRS”):
FSIRS amounts reclassified to net income, net of tax	0	414	416	827	1,241	2,023
Net forward-starting interest rate swaps	0	414	416	827	1,241	2,023
Total other comprehensive income (loss), net of tax	(1,556)	2,700	1,233	5,315	10,160	(71)
Comprehensive income (loss)	(7,637)	29,174	92,402	150,634	163,212	271,347
Foreign currency translation adjustments	(2,680)	909	(1,433)	1,732	(3,145)	5,656
Comprehensive income attributable to noncontrolling interests	494	1,355	1,566	2,907	5,082	7,189
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(8,131)	27,819	90,836	147,727	158,130	264,158
Southwest Gas Corporation
Net income (loss)	(2,266)	11,413	109,529	130,128	166,536	193,705
Defined benefit pension plans:
Net actuarial gain (loss)	0	0	0	0	44,974	(43,730)
Amortization of prior service cost	33	182	66	364	431	802
Amortization of net actuarial loss	6,615	8,472	13,231	16,946	30,179	31,322
Regulatory adjustment	(5,524)	(7,277)	(11,047)	(14,554)	(63,520)	3,856
Net defined benefit pension plans	1,124	1,377	2,250	2,756	12,064	(7,750)
Forward-starting interest rate swaps (“FSIRS”):
FSIRS amounts reclassified to net income, net of tax	0	414	416	827	1,241	2,023
Net forward-starting interest rate swaps	0	414	416	827	1,241	2,023
Total other comprehensive income (loss), net of tax	1,124	1,791	2,666	3,583	13,305	(5,727)
Comprehensive income (loss)	$ (1,142)	$ 13,204	$ 112,195	$ 133,711	$ 179,841	$ 187,978

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - Southwest - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	$ 91,169	$ 145,319	$ 153,052	$ 271,418
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	230,656	176,290	425,407	343,447
Deferred income taxes	30,163	44,178	47,197	63,774
Changes in current assets and liabilities:
Accounts receivable, net of allowance	(42,212)	10,005	(103,771)	(29,021)
Accrued utility revenue	44,900	43,900	(1,500)	(2,700)
Deferred purchased gas costs	(64,176)	(287,687)	(120,217)	(305,043)
Accounts payable	(33,356)	(41,075)	58,145	(1,571)
Accrued taxes	(5,023)	(3,164)	(8,584)	2,988
Other current assets and liabilities	16,480	(31,928)	(40,801)	(3,039)
Gain on sale of property	(3,475)	(4,033)	(6,348)	(5,572)
Changes in undistributed stock compensation	7,036	5,736	10,594	8,518
Equity AFUDC	(575)	0	(575)	(2,543)
Changes in deferred charges and other assets	13,736	(11,171)	11,366	(35,494)
Changes in other liabilities and deferred credits	(21,705)	(45,013)	(50,321)	(52,865)
Net cash provided by operating activities	263,618	1,357	373,644	252,297
CASH FLOW FROM INVESTING ACTIVITIES:
Construction expenditures and property additions	(367,932)	(338,049)	(745,509)	(739,719)
Changes in customer advances	17,051	7,507	25,518	17,442
Other	3,905	9,159	13,002	13,367
Net cash used in investing activities	(365,785)	(321,383)	(3,080,058)	(708,910)
CASH FLOW FROM FINANCING ACTIVITIES:
Dividends paid	(77,419)	(67,130)	(148,511)	(131,189)
Issuance of long-term debt, net	759,602	82,245	2,338,053	124,319
Retirement of long-term debt	(412,263)	(60,500)	(804,427)	(299,370)
Change in credit facility and commercial paper	(130,000)	0	(150,000)	150,000
Withholding remittance - share-based compensation	(2,089)	(1,243)	(2,110)	(1,243)
Other	(12,811)	(1,623)	(11,917)	(3,565)
Net cash provided by financing activities	95,398	284,051	2,874,805	304,001
Change in cash and cash equivalents	(6,734)	(35,787)	168,398	(152,026)
Cash and cash equivalents at beginning of period	222,697	83,352	47,565	199,591
Cash and cash equivalents at end of period	215,963	47,565	215,963	47,565
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	92,297	47,475	149,174	101,227
Income taxes paid (received), net	8,300	6,659	5,849	15,118
Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	109,529	130,128	166,536	193,705
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	128,044	126,329	255,113	243,701
Deferred income taxes	36,624	38,178	51,683	64,989
Changes in current assets and liabilities:
Accounts receivable, net of allowance	27,846	28,018	(22,978)	(25,096)
Accrued utility revenue	44,900	43,900	(1,500)	(2,700)
Deferred purchased gas costs	(63,426)	(287,687)	(119,467)	(305,043)
Accounts payable	(72,201)	(56,518)	42,081	6,812
Accrued taxes	(181)	2,401	5,171	(16,872)
Other current assets and liabilities	46,730	4,549	(28,090)	(18,418)
Gain on sale of property	(1,503)	0	(1,503)	0
Changes in undistributed stock compensation	4,459	4,159	6,692	5,959
Equity AFUDC	(157)	0	(157)	(2,543)
Changes in deferred charges and other assets	2,529	(17,540)	(8,674)	(48,142)
Changes in other liabilities and deferred credits	(22,230)	(45,309)	(49,307)	(55,272)
Net cash provided by operating activities	240,963	(29,392)	295,600	41,080
CASH FLOW FROM INVESTING ACTIVITIES:
Construction expenditures and property additions	(293,197)	(276,109)	(619,071)	(613,824)
Changes in customer advances	17,051	7,507	25,517	17,442
Other	(896)	6	(934)	677
Net cash used in investing activities	(277,042)	(268,596)	(594,488)	(595,705)
CASH FLOW FROM FINANCING ACTIVITIES:
Contributions from parent	0	115,641	86,942	194,063
Dividends paid	(60,200)	(53,500)	(118,100)	(106,900)
Issuance of long-term debt, net	593,862	0	891,180	0
Retirement of long-term debt	(275,000)	0	(275,000)	(125,000)
Change in credit facility and commercial paper	(130,000)	0	(150,000)	150,000
Change in short-term debt	(25,000)	234,000	(66,000)	291,000
Withholding remittance - share-based compensation	(1,996)	(1,242)	(2,017)	(1,242)
Other	(2,135)	(263)	(3,692)	(362)
Net cash provided by financing activities	99,531	294,636	363,313	401,559
Change in cash and cash equivalents	63,452	(3,352)	64,425	(153,066)
Cash and cash equivalents at beginning of period	38,691	41,070	37,718	190,784
Cash and cash equivalents at end of period	102,143	37,718	102,143	37,718
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	51,312	44,834	96,718	94,984
Income taxes paid (received), net	$ 5	$ 0	$ (13,524)	$ 3,359

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - Southwest - USD ($) $ in Thousands	Total	Southwest Gas Corporation	Common stock shares	Common stock shares Southwest Gas Corporation	Additional paid-in capital	Additional paid-in capital Southwest Gas Corporation	Accumulated other comprehensive loss	Accumulated other comprehensive loss Southwest Gas Corporation	Retained earnings	Retained earnings Southwest Gas Corporation
Beginning balance (in shares) at Dec. 31, 2020			57,193,000
Beginning balance at Dec. 31, 2020			$ 58,823		$ 1,609,155	$ 1,410,345	$ (61,003)	$ (61,135)	$ 1,067,978	$ 835,146
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)									142,412	130,128
Share-based compensation						3,433				(517)
Contributions from Southwest Gas Holdings, Inc.						115,641
Dividends declared to Southwest Gas Holdings, Inc.									(70,205)	(56,000)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax							2,756	2,756
FSIRS amounts reclassified to net income, net of tax	$ 827	$ 827					827	827
Ending balance (in shares) at Jun. 30, 2021			59,088,000	47,482,000
Ending balance at Jun. 30, 2021		2,429,736	$ 60,718	$ 49,112	1,733,572	1,529,419	(55,688)	(57,552)	1,108,279	908,757
Beginning balance (in shares) at Mar. 31, 2021			57,995,000
Beginning balance at Mar. 31, 2021			$ 59,625		1,660,108	1,458,344	(58,388)	(59,343)	1,112,377	926,011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)									25,119	11,413
Share-based compensation						1,418				(167)
Contributions from Southwest Gas Holdings, Inc.						69,657
Dividends declared to Southwest Gas Holdings, Inc.									(35,329)	(28,500)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax							1,377	1,377
FSIRS amounts reclassified to net income, net of tax	414	414					414	414
Ending balance (in shares) at Jun. 30, 2021			59,088,000	47,482,000
Ending balance at Jun. 30, 2021		2,429,736	$ 60,718	$ 49,112	1,733,572	1,529,419	(55,688)	(57,552)	1,108,279	908,757
Increase (Decrease) in Stockholders' Equity [Roll Forward]
FSIRS amounts reclassified to net income, net of tax	$ 1,241	1,241
Ending balance (in shares) at Jun. 30, 2022	67,003,792		67,004,000	47,482,000
Ending balance at Jun. 30, 2022		2,579,596	$ 68,634	$ 49,112	2,279,493	1,622,006	(45,528)	(44,247)	1,156,253	952,725
Beginning balance (in shares) at Dec. 31, 2021	60,422,081		60,422,000
Beginning balance at Dec. 31, 2021			$ 62,052		1,824,216	1,618,911	(46,761)	(46,913)	1,114,313	906,827
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)									89,603	109,529
Share-based compensation						3,095				(631)
Contributions from Southwest Gas Holdings, Inc.						0
Dividends declared to Southwest Gas Holdings, Inc.									(83,641)	(63,000)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax							2,250	2,250
FSIRS amounts reclassified to net income, net of tax	$ 416	416					416	416
Ending balance (in shares) at Jun. 30, 2022	67,003,792		67,004,000	47,482,000
Ending balance at Jun. 30, 2022		2,579,596	$ 68,634	$ 49,112	2,279,493	1,622,006	(45,528)	(44,247)	1,156,253	952,725
Beginning balance (in shares) at Mar. 31, 2022			66,849,000
Beginning balance at Mar. 31, 2022			$ 68,479		2,273,837	1,620,616	(43,972)	(45,371)	1,190,738	987,177
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)									(6,575)	(2,266)
Share-based compensation						1,390				(186)
Contributions from Southwest Gas Holdings, Inc.						0
Dividends declared to Southwest Gas Holdings, Inc.									(41,732)	(32,000)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax							1,124	1,124
FSIRS amounts reclassified to net income, net of tax	$ 0	0					0	0
Ending balance (in shares) at Jun. 30, 2022	67,003,792		67,004,000	47,482,000
Ending balance at Jun. 30, 2022		$ 2,579,596	$ 68,634	$ 49,112	$ 2,279,493	$ 1,622,006	$ (45,528)	$ (44,247)	$ 1,156,253	$ 952,725

- Definition

Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

+ References

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+ Details

Background, Organization, and Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Background, Organization, and Summary of Significant Accounting Policies

Note 1 – Background, Organization, and Summary of Significant Accounting Policies

Nature of Operations. Southwest Gas Holdings, Inc. (together with its subsidiaries, the “Company”) is a holding company, owning all of the shares of common stock of Southwest Gas Corporation (“Southwest” or the “natural gas distribution” segment), all of the shares of common stock of Centuri Group, Inc. (“Centuri,” or the “utility infrastructure services” segment), and all of the shares of common stock of MountainWest Pipelines Holding Company (“MountainWest,” or the “pipeline and storage” segment).

The Company completed the acquisition of Dominion Energy Questar Pipeline, LLC and related entities (“Questar Pipelines”) in December 2021. Following the completion of the acquisition, the Company formed MountainWest which owns all of the membership interests in Questar Pipelines. In April 2022, the Company completed a general rebranding of the Questar Pipelines entities under the MountainWest name. The acquired operations further diversify the Company’s business in the midstream sector, with an expansion of interstate natural gas pipelines and underground storage services, primarily composed of regulated operations under the jurisdiction of the Federal Energy Regulatory Commission (the “FERC”), thereby expanding natural gas transportation services into Utah, Wyoming, and Colorado. See Note 8 - Business Acquisitions for more information.

Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. Results for the natural gas distribution segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures.

Centuri is a strategic utility infrastructure services company dedicated to partnering with North America’s gas and electric providers to build and maintain the energy network that powers millions of homes across the United States (“U.S.”) and Canada. Centuri derives revenue primarily from installation, replacement, repair, and maintenance of energy networks. Centuri operates in the U.S., primarily as NPL, Neuco, Linetec, and Riggs Distler, and in Canada, primarily as NPL Canada. Utility infrastructure services activity is seasonal in many of Centuri’s operating areas. Peak periods are the summer and fall months in colder climate areas, such as the northeastern and midwestern U.S. and in Canada. In warmer climate areas, such as the southwestern and southeastern U.S., utility infrastructure services activity continues year round.

Centuri completed the acquisition of Drum Parent LLC (“Drum”), including Drum’s most significant operating subsidiary, Riggs Distler, in August 2021, thereby expanding Centuri’s electric infrastructure services footprint in the northeast and mid-Atlantic regions of the U.S. See Note 8 - Business Acquisitions for more information.

In March 2022, the Company announced that its Board of Directors (the “Board”) had determined to separate Centuri from the Company and authorized management to complete the separation within nine to twelve months. Initially it was contemplated that the Centuri separation would take the form of a spin-off. Then, in April 2022, as a result of interest in the Company well in excess of an earlier tender offer to other shareholders by an activist stockholder (affiliates of Carl C. Icahn), the Board authorized the review of a full range of strategic alternatives to maximize stockholder value. As part of this process, a strategic transactions committee of the Board (the “Strategic Transactions Committee”), consisting entirely of independent directors, has been evaluating a sale of the Company, as well as a range of alternatives, including, but not limited to, a separate sale of its business units and/or pursuing the spin-off of Centuri (collectively, the “Strategic Review”). On August 3, 2022, the Company announced that the Board had unanimously determined that the best path forward to maximize value for all stockholders is to (i) focus on the strategic plan and conclude the strategic review process for Southwest Gas Holdings, Inc. and Southwest Gas Corporation; (ii) continue to review strategic alternatives for MountainWest; and (iii) continue to review strategic alternatives for Centuri, including a sale or spin-off of Centuri.

On May 6, 2022, the Company entered into a Cooperation Agreement (the “Cooperation Agreement”) with Carl C. Icahn and the persons and entities referenced therein (collectively, the “Icahn Group”). In accordance with the Cooperation Agreement, among other things, John P. Hester, President and Chief Executive Officer of the Company and Southwest, retired from his positions with the Company and Southwest and resigned from the Board. Thereafter, Karen S. Haller, the Company’s former Executive Vice President/Chief Legal and Administrative Officer, was appointed President and Chief Executive Officer of the Company and Chief Executive Officer of Southwest, and was appointed as a member of the Board effective immediately following the completion of the Company’s 2022 annual meeting of stockholders (the “2022 Annual Meeting”). Justin L. Brown, formerly Southwest’s Senior Vice President/General Counsel, was appointed as President of Southwest.

In addition, pursuant to the Cooperation Agreement, the Company agreed to appoint three new directors, Andrew W. Evans, H. Russell Frisby, Jr., and Henry P. Linginfelter (collectively, the “Icahn Designees”), to the Board, which became effective immediately following the 2022 Annual Meeting. Also pursuant to the Cooperation Agreement, on May 27, 2022, the Icahn group informed the Company that it would cause Mr. Frisby to resign from the Board and requested that Andrew J. Teno be

appointed to the Board to fill the vacancy created by Mr. Frisby’s resignation. As a result, on May 27, Mr. Frisby resigned from the Board, effective immediately, and the Board appointed Mr. Teno to fill the vacancy created by Mr. Frisby’s resignation, effective immediately. The Icahn Group’s ability to designate directors to the Board is subject to certain ownership thresholds. Consistent with the May 6, 2022 Cooperation Agreement with the Icahn Group, the Company expects José A. Cárdenas to step down from the Board in the near future, and a new director will be appointed.

The Cooperation Agreement required the Board expand the Strategic Transactions Committee from three directors to six directors, comprised of the existing members of the Strategic Transactions Committee in addition to the three Icahn Designees. Also, as the Icahn Group has the ability to designate at least three members of the Board, such individuals are to be included on the Strategic Transactions Committee. If the Icahn Group may only designate two members of the Board, then both would serve on the Strategic Transactions Committee.

On May 9, 2022, the Company also entered into Amendment No. 1 to the Rights Agreement dated October 10, 2021 (the “Original Rights Agreement” and as amended, the “Amended Rights Agreement”), to increase the triggering percentage from 10% to 24.9% pursuant to the terms of the Cooperation Agreement and permit the subsequent consummation of the Offer (as defined below). See details in the Company’s and Southwest’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 (the “2021 Form 10-K”) regarding the Original Rights Agreement, as well as Note 4 – Common Stock in this current report on Form 10-Q.

In addition, pursuant to the Cooperation Agreement, the Icahn Group is permitted to acquire up to 24.9% of the shares of the Company, which would include shares as part of an updated tender offer of $82.50 per share, with the updated tender offer expiring on May 20, 2022. An earlier civil suit (initiated in November 2021) by Icahn entities against the Company and certain directors and officers of the Company was subject to a stipulation of dismissal as part of the Cooperation Agreement. The Cooperation Agreement also provides for the reimbursement by the Company of certain out-of-pocket third-party expenses, including certain legal fees, incurred by the Icahn Group.

Basis of Presentation. The condensed consolidated financial statements of Southwest Gas Holdings, Inc. and subsidiaries and Southwest included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). The year-end 2021 condensed balance sheet data was derived from audited financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. No substantive change has occurred with regard to the Company’s business segments on the whole during the recently completed quarter.

The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments, consisting of normal recurring items and estimates necessary for a fair depiction of results for the interim periods, have been made.

These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the 2021 Annual Report to Stockholders, which is incorporated by reference into the 2021 Form 10-K.

Other Property and Investments. Other property and investments on Southwest’s and the Company’s Condensed Consolidated Balance Sheets includes:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Net cash surrender value of COLI policies	$	142,819	$	149,947
Other property	3,780		3,146
Total Southwest Gas Corporation	146,599		153,093
Non-regulated property, equipment, and intangibles	1,678,683		1,616,392
Non-regulated accumulated provision for depreciation and amortization	(569,630)		(512,343)
Other property and investments	57,049		59,337
Total Southwest Gas Holdings, Inc.	$	1,312,701	$	1,316,479

Included in the table above are the net cash surrender values of company-owned life insurance (“COLI”) policies. These life insurance policies on members of management and other key employees are used by Southwest to indemnify itself against the loss of talent, expertise, and knowledge, as well as to provide indirect funding for certain nonqualified benefit plans. The term

non-regulated in regard to assets and related balances in the table above is in reference to the non-rate regulated operations of Centuri, and to a more limited extent, certain assets of MountainWest.

Cash and Cash Equivalents. Cash and cash equivalents include money market fund investments totaling approximately $77 million and $97 million, for Southwest and the Company, respectively, at June 30, 2022, and $20 million for the Company as of December 31, 2021. The balance for Southwest as of December 31, 2021 was insignificant. These investments fall within Level 2 of the fair value hierarchy, due to the asset valuation methods used by money market funds.

Non-cash investing activities for the Company and Southwest include capital expenditures that were not yet paid, thereby remaining in accounts payable, which declined by approximately $11.6 million and $18.3 million, respectively, during the six months ended June 30, 2022, and increased $6.5 million and $6.6 million, respectively, during the twelve months ended June 30, 2022.

Accounts Receivable, net of allowances. Following an earlier moratorium on account disconnections amidst the COVID-19 environment, account collection efforts resumed in 2021 in all jurisdictions in which Southwest operates. Ultimately, some accounts may not be collected, and if so, would be written off. Estimates as to collectibility are made on an ongoing basis. However, Southwest continues to actively work with customers experiencing financial hardship by means of flexible payment options and partnering with assistance agencies. The cost of gas included in customer rates also influences account balances at each reporting date.

Deferred Purchased Gas Costs. The various regulatory commissions have established procedures to enable the rate-regulated companies to adjust billing rates for changes in the cost of natural gas purchased. The difference between the current cost of gas purchased and the cost of gas recovered in billed rates is deferred. Generally, these deferred amounts are recovered or refunded within one year.

Prepaid and other current assets. Prepaid and other current assets for Southwest include, among other things, materials and operating supplies of $70.2 million at June 30, 2022 and $62.9 million at December 31, 2021 (carried at weighted average cost). For the Company, there were materials and operating supplies of $74.5 million and $67.4 million at June 30, 2022 and December 31, 2021, respectively, which included amounts for MountainWest. Also included in the balance for both Southwest and the Company was $10.2 million and $52 million as of June 30, 2022 and December 31, 2021, respectively, in accrued purchased gas cost.

Goodwill. Goodwill is assessed as of October 1st each year for impairment, or more frequently, if circumstances indicate an impairment to the carrying value of goodwill may have occurred. Management of the Company and Southwest considered its reporting units and segments, determining that they remained consistent between periods presented below, and that no change was necessary with regard to the level at which goodwill is assessed for impairment. The acquisition of MountainWest resulted in a new reportable segment which is assessed for impairment beginning in 2022. Since December 31, 2021, management qualitatively assessed whether events during the first six months of 2022 may have resulted in conditions whereby the carrying value of goodwill was higher than its fair value, which if the case, could be an indication of a permanent impairment. Through this assessment, no such condition was believed to have existed and therefore, no impairment was deemed to have occurred. However, there can be no assurances that future assessments of goodwill will not result in an impairment, and various factors, including the results of the continuing Strategic Review related to Centuri and MountainWest, or changes in economic conditions, governmental monetary policies, interest rates, or others, on their own or in combination with the undertakings of the Strategic Review, could result in the fair value of the related reporting units being lower than their carrying value. See also Note 8 - Business Acquisitions. Goodwill in the Natural Gas Distribution operations of Southwest, and across all operations of the Company, is included in their respective Condensed Consolidated Balance Sheets as follows:


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Total Company
December 31, 2021	$	10,095	$	785,058	$	986,179	$	1,781,332
Measurement-period adjustments from Riggs Distler acquisition (a)	—		(906)				(906)
Measurement-period adjustments from MountainWest acquisition (a)	—		—		(28,178)		(28,178)
Foreign currency translation adjustment	—		(1,776)		—		(1,776)
June 30, 2022	$	10,095	$	782,376	$	958,001	$	1,750,472

(a) See Note 8 - Business Acquisitions for details regarding measurement-period adjustments.

Other Current Liabilities. Management recognizes in its balance sheets various liabilities that are expected to be settled through future cash payment within the next twelve months, including amounts payable under regulatory mechanisms, customary accrued expenses for employee compensation and benefits, declared but unpaid dividends, and miscellaneous other accrued liabilities. Other current liabilities for the Company include $41.5 million and $36 million of dividends declared as of June 30, 2022 and December 31, 2021, respectively.

Other Income (Deductions). The following table provides the composition of significant items included in Other income (deductions) in Southwest’s and the Company’s Condensed Consolidated Statements of Income:


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Southwest Gas Corporation:
Change in COLI policies	$	(5,200)	$	3,100	$	(7,200)	$	5,800	$	(4,200)	$	18,500
Interest income	3,198		1,231		5,999		1,947		9,165		4,160
Equity AFUDC	81		(981)		157		—		157		2,543
Other components of net periodic benefit cost	(187)		(3,505)		(375)		(7,010)		(7,386)		(17,021)
Miscellaneous income and (expense)	(1,325)		(1,010)		(699)		(1,352)		(3,798)		(2,689)
Southwest Gas Corporation - total other income (deductions)	(3,433)		(1,165)		(2,118)		(615)		(6,062)		5,493
Centuri, MountainWest, and Southwest Gas Holdings, Inc.:

Foreign transaction gain (loss)	214		(9)		217		(12)		207		(12)
Equity AFUDC	236		—		418		—		418		—
Equity in earnings of unconsolidated investments	728		109		1,243		101		1,368		156
Miscellaneous income and (expense)	(580)		(246)		(1,351)		(337)		(158)		(444)
Southwest Gas Holdings, Inc. - total other income (deductions)	$	(2,835)	$	(1,311)	$	(1,591)	$	(863)	$	(4,227)	$	5,193

Included in the table above is the change in cash surrender values of COLI policies (including net death benefits recognized). Current tax regulations provide for tax-free treatment of life insurance (death benefit) proceeds. Therefore, changes in the cash surrender values of COLI policies, as they progress towards the ultimate death benefits, are also recorded without tax consequences. Refer also to the discussion of Other Property and Investments above and to Note 2 – Components of Net Periodic Benefit Cost.

Redeemable Noncontrolling Interests. In connection with the acquisition of Linetec in November 2018, the previous owner retained a 20% equity interest in that entity, the reduction of which is subject to certain rights based on the passage of time or upon the occurrence of certain triggering events. Effective January 2022, the Company, through Centuri, had the right, but not the obligation, to purchase at fair value (subject to a floor) a portion of the interest held by the previous owner, and in incremental amounts each year thereafter. In March 2022, the parties agreed to a partial redemption based on these provisions, and as a result, Centuri paid $39.6 million to the previous owner of Linetec for a 5% equity interest in Linetec, thereby reducing the balance continuing to be redeemable to 15% under the terms of the original agreement. In order to fund the redemption, Southwest Gas Holdings, Inc. contributed capital to Centuri.

Certain members of Riggs Distler management have a 1.42% interest in Drum, which is redeemable, subject to certain rights based on the passage of time or upon the occurrence of certain triggering events.

Significant changes in the value of the redeemable noncontrolling interests, above a floor determined at the establishment date, are recognized as they occur, and the carrying value is adjusted as necessary at each reporting date. The fair value is estimated using a market approach that utilizes certain financial metrics from guideline public companies of similar industry and operating characteristics. Based on the fair value model employed, the estimated redemption value of the Linetec redeemable noncontrolling interest decreased by approximately $36 million during the six months ended June 30, 2022. Adjustment to the redemption value also impacts retained earnings, as reflected in the Company’s Condensed Consolidated Statement of Equity, but does not impact net income. The following depicts changes to the balances of the redeemable noncontrolling interests:


(Thousands of dollars):	Linetec		Drum		Total
Balance, December 31, 2021	$	184,148	$	12,569	$	196,717
Net income (loss) attributable to redeemable noncontrolling interests	1,576		(10)		1,566
Redemption value adjustments	(35,978)		—		(35,978)
Redemption of equity interest from noncontrolling party	(39,649)		—		(39,649)
Balance, June 30, 2022	$	110,097	$	12,559	$	122,656

Earnings Per Share. Basic earnings per share (“EPS”) in each period of this report were calculated by dividing net income attributable to Southwest Gas Holdings, Inc. by the weighted-average number of shares during those periods. Diluted EPS includes additional weighted-average common stock equivalents (performance shares and restricted stock units). Unless otherwise noted, the term “Earnings Per Share” refers to Basic EPS. A reconciliation of the denominator used in Basic and Diluted EPS calculations is shown in the following table:


	Three Months Ended June 30,		Six Months Ended June 30,		Twelve Months Ended June 30,
(In thousands)	2022	2021	2022	2021	2022	2021
Weighted average basic shares	67,045	58,607	63,909	58,106	62,022	57,348
Effect of dilutive securities:
Restricted stock units (1)	145	103	132	91	135	92
Weighted average diluted shares	67,190	58,710	64,041	58,197	62,157	57,440

(1) The number of securities included 136,000 and 95,000 performance shares during the three months ending June 30, 2022 and 2021, 125,000 and 85,000 performance shares during the six months ending June 30, 2022 and 2021 and 124,000 and 83,000 performance shares during the twelve months ending June 30, 2022 and 2021, respectively, the total of which was derived by assuming that target performance will be achieved during the relevant performance period.

Contingencies. Southwest maintains liability insurance for various risks associated with the operation of its natural gas pipelines and facilities. In connection with these liability insurance policies, Southwest is responsible for an initial deductible or self-insured retention amount per incident, after which the insurance carriers would be responsible for amounts up to the policy limits. For the policy year August 2021 to July 2022, these liability insurance policies require Southwest to be responsible for the first $1 million (self-insured retention) of each incident plus the first $4 million in aggregate claims above its self-insured retention in the policy year. In August 2021, a natural gas pipe operated by Southwest was involved in an explosion that injured four individuals and damaged property. The explosion was caused by a leak in the pipe, and is under investigation. Individuals that were injured have each brought legal claims against Southwest and other parties. If Southwest is deemed fully or partially responsible, Southwest estimates its net exposure could be equal to the self-insured retention of $5 million (the maximum noted above). In 2021, pursuant to Accounting Standards Codification 450, Contingencies, Southwest recorded a $5 million liability related to this incident reflecting the maximum noted above; an estimate of actual loss greater than this exposure (to be covered by insurance) cannot be estimated as of the date these financial statements are issued.

Other contingencies are also recognized where appropriate, if claims are brought, or expected to be brought, against the Company or Southwest, where management expects it may settle (or be required to settle) claims in cash, or in some cases, by means of insurance indemnification. The balance of such reserves was updated for additional accruals, including in regard to a contract dispute. For that item, $6.2 million was recorded during the second quarter of 2022, based on management’s estimate of Southwest’s exposure.

As described above, the November 2021 civil suit filed by the Icahn Group, against the Company and certain officers and directors, was subject to a stipulation of dismissal with prejudice in May 2022, pursuant to the terms of the Cooperation Agreement.

On November 18, 2021, the City Pension Fund for Firefighters and Police Officers in the City of Miami Beach (“City Pension Fund”) commenced a putative class action lawsuit in the Court of Chancery for the State of Delaware on behalf of a putative class of persons who purchased the Company’s stock. The complaint was later amended on November 30, 2021. The amended complaint named the Company and the individual members of the Board as defendants. The complaint sought to assert breach of fiduciary duty claims, alleging that the Board’s recommendation that stockholders reject Icahn’s Offer to purchase shares of the Company’s common stock omitted material information about the Company’s financial analysis; and sought to have the Board approve Icahn’s slate of nominees as “continuing directors” under certain of the Company’s debt instruments. In March 2022, the City Pension Fund filed a motion for summary judgment on its claim; however, in April 2022, the City Pension Fund

filed a notice of withdrawal of its motion for summary judgment. The Company believes that the claims lack merit and intends to vigorously defend against them.

Recent Accounting Standards Updates.

Accounting pronouncements effective or adopted in 2022:

In March 2020, the Financial Accounting Standards Board (the “FASB”) issued ASU 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” The update provides optional guidance for a limited time to ease the potential burden in accounting for, or recognizing the effects of, reference rate reform on financial reporting, including when modifying a contract (during the eligibility period covered by the update to Topic 848) to replace a reference rate affected by such reform. The update applies only to contracts and hedging relationships that reference the London Interbank Offered Rate (“LIBOR”) or another rate expected to be discontinued due to reference rate reform. The guidance was eligible to be applied upon issuance on March 12, 2020, and can generally be applied through December 31, 2022, and while a proposal by the FASB has occurred to extend the optional guidance to the full tenor of LIBOR expiration dates occurring after 2022, to date, no such update has been made effective. Management will monitor the impacts this update might have on the Company’s and Southwest’s consolidated financial statements and disclosures, and will reflect such appropriately, in the event that the optional guidance is elected. Management will also monitor further FASB action, if any, in regard to the full tenor of LIBOR expiration dates. See also LIBOR discussion in Note 5 – Debt.

In August 2020, the FASB issued ASU 2020-06 “Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity.” The update, amongst other amendments, improves the guidance related to the disclosures and earnings-per-share for convertible instruments and contracts in an entity’s own equity. The Company and Southwest adopted the update in the first quarter of 2022, the impact of which was not material to the consolidated financial statements of the Company or Southwest.

Components of Net Periodic Benefit Cost

6 Months Ended

Jun. 30, 2022

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost

Note 2 – Components of Net Periodic Benefit Cost

Southwest has a noncontributory qualified retirement plan with defined benefits covering substantially all employees and a separate unfunded supplemental retirement plan (“SERP”) which is limited to officers. Southwest also provides postretirement benefits other than pensions (“PBOP”) to its qualified retirees for health care, dental, and life insurance. The defined benefit qualified retirement plan, SERP, and PBOP are not available to Southwest employees hired on or after January 1, 2022. Employees hired in 2022 or later periods are eligible for enhanced defined contributions as part of the Southwest 401(k) plan, rather than participating in the defined benefit retirement plan.

The service cost component of net periodic benefit costs included in the table below is a component of an overhead loading process associated with the cost of labor. The overhead process ultimately results in allocation of service cost to the same accounts to which productive labor is charged. As a result, service costs become components of various accounts, primarily operations and maintenance expense, net regulated operations plant, and deferred charges and other assets for both the Company and Southwest. The other components of net periodic benefit cost are reflected in Other income (deductions) on the Condensed Consolidated Statements of Income of each entity.


	Qualified Retirement Plan
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	11,028	$	10,290	$	22,056	$	20,580	$	42,635	$	37,730
Interest cost	11,251		10,108		22,502		20,216		42,718		42,994
Expected return on plan assets	(19,978)		(18,088)		(39,956)		(36,176)		(76,132)		(68,824)
Amortization of net actuarial loss	8,117		10,489		16,234		20,978		37,211		38,990
Net periodic benefit cost	$	10,418	$	12,799	$	20,836	$	25,598	$	46,432	$	50,890

	SERP
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	106	$	132	$	212	$	263	$	475	$	457
Interest cost	360		358		720		716		1,435		1,517
Amortization of net actuarial loss	587		660		1,175		1,320		2,497		2,223
Net periodic benefit cost	$	1,053	$	1,150	$	2,107	$	2,299	$	4,407	$	4,197

	PBOP
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	485	$	423	$	970	$	846	$	1,815	$	1,636
Interest cost	613		548		1,226		1,096		2,323		2,388
Expected return on plan assets	(807)		(810)		(1,614)		(1,620)		(3,233)		(3,324)
Amortization of prior service costs	44		240		88		480		567		1,057

Net periodic benefit cost	$	335	$	401	$	670	$	802	$	1,472	$	1,757

Revenue

6 Months Ended

Jun. 30, 2022

Revenue from Contract with Customer [Abstract]

Revenue

Note 3 – Revenue

The following information about the Company’s revenues is presented by segment. Southwest encompasses the natural gas distribution segment, Centuri encompasses the utility infrastructure services segment, and MountainWest encompasses the pipeline and storage segment. Certain disclosures, where materially consistent with those provided most recently in the 2021 Form 10-K, are not repeated below.

Natural Gas Distribution Segment:

Southwest’s operating revenues included on the Condensed Consolidated Statements of Income of both the Company and Southwest include revenue from contracts with customers, which is shown below, disaggregated by customer type, in addition to other categories of revenue:


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Residential	$	228,573	$	193,322	$	743,159	$	596,465	$	1,182,306	$	995,132
Small commercial	78,730		56,093		202,714		137,491		335,437		235,114
Large commercial	20,989		13,158		41,150		25,831		72,690		47,818
Industrial/other	10,773		6,974		20,745		20,744		42,314		33,785
Transportation	24,466		21,797		51,098		46,333		97,005		90,307
Revenue from contracts with customers	363,531		291,344		1,058,866		826,864		1,729,752		1,402,156
Alternative revenue program revenues (deferrals)	11,022		(1,531)		(12,477)		(17,904)		18,608		(6,110)
Other revenues (1)	3,389		2,983		8,092		5,768		13,183		4,006
Total Regulated operations revenues	$	377,942	$	292,796	$	1,054,481	$	814,728	$	1,761,543	$	1,400,052

(1) Amounts include late fees and other miscellaneous revenues, and may also include the impact of certain regulatory mechanisms, such as cost-of-service components in customer rates expected to be returned to customers in future periods. Also includes the impacts of a temporary moratorium on late fees and disconnection for nonpayment during the COVID-19 pandemic.

Utility Infrastructure Services Segment:

The following tables display Centuri’s revenue, reflected as Utility infrastructure services revenues on the Condensed Consolidated Statements of Income of the Company, representing revenue from contracts with customers disaggregated by service and contract types:


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Service Types:
Gas infrastructure services	$	418,869	$	346,877	$	679,551	$	568,714	$	1,413,177	$	1,282,008
Electric power infrastructure services	179,749		97,644		361,717		191,605		695,314		435,825
Other	107,472		84,104		188,699		132,281		387,537		294,749
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967	$	892,600	$	2,496,028	$	2,012,582


	Three Months Ended June 30,				Six Months Ended June 30,					Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022			2021		2022			2021
Contract Types:
Master services agreement	$	617,489	$	398,650	$	1,062,834	*	$	692,330	$	2,023,482	*	$	1,543,292
Bid contract	88,601		129,975		167,133		*	200,270		472,546		*	469,290
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967		$	892,600	$	2,496,028		$	2,012,582

Unit price contracts	$	421,927	$	361,926	$	724,450		$	596,375	$	1,497,157		$	1,344,626
Fixed price contracts	128,793		50,455		215,330			85,049		398,023			179,194
Time and materials contracts	155,370		116,244		290,187			211,176		600,848			488,762
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967		$	892,600	$	2,496,028		$	2,012,582

* The Company identified an error in the first quarter 2022 disclosure which resulted in an understatement of $88.8 million in the master services agreement category and an overstatement by the same amount in the bid contract category. Management concluded this item was not material to the previously issued financial statements and will revise the first quarter 2022 amounts in future filings.

The following table provides information about contracts receivable and revenue earned on contracts in progress in excess of billings (contract assets), both of which are included within Accounts receivable, net of allowances, as well as amounts billed in excess of revenue earned on contracts (contract liabilities), which are included in Other current liabilities as of June 30, 2022 and December 31, 2021 on the Company’s Condensed Consolidated Balance Sheets:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Contracts receivable, net	$	332,433	$	296,005
Revenue earned on contracts in progress in excess of billings	254,259		214,774
Amounts billed in excess of revenue earned on contracts	13,738		11,860

The revenue earned on contracts in progress in excess of billings (contract asset) primarily relates to Centuri’s right to consideration for work completed but not billed and/or approved for billing at the reporting date. These contract assets are transferred to contracts receivable when the rights become unconditional. The amounts billed in excess of revenue earned (contract liability) primarily relate to the advance consideration received from customers for which work has not yet been completed. The change in this contract liability balance from December 31, 2021 to June 30, 2022 is due to increases in cash received, net of revenue recognized, from contracts that commenced during the period, offset by revenue recognized of approximately $11.9 million that was included in this balance as of January 1, 2022, after which time it became earned and the balance was reduced.

For contracts that have an original duration of one year or less, Centuri uses the practical expedient applicable to such contracts and does not consider/compute an interest component based on the time value of money. Furthermore, because of the short duration of these contracts, Centuri has not disclosed the transaction price for the remaining performance obligations as of the end of each reporting period or when the Company expects to recognize the revenue.

As of June 30, 2022, Centuri had 47 fixed price contracts with an original duration of more than one year. The aggregate amount of the transaction price allocated to the unsatisfied performance obligations of these contracts as of June 30, 2022 was $465.7 million. Centuri expects to recognize the remaining performance obligations over approximately the next 2.9 years; however, the timing of that recognition is largely within the control of the customer, including when the necessary equipment and materials required to complete the work are provided by the customer.

Utility infrastructure services contracts receivable consists of the following:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Billed on completed contracts and contracts in progress	$	331,173	$	292,770
Other receivables	1,408		3,492
Contracts receivable, gross	332,581		296,262
Allowance for doubtful accounts	(148)		(257)
Contracts receivable, net	$	332,433	$	296,005

Pipeline and Storage Segment:

MountainWest derives revenue on the basis of services rendered, commodities delivered, or contracts settled and includes amounts yet to be billed to customers. MountainWest generates revenue and earnings from annual reservation payments under firm peaking storage and firm transportation contracts. Straight-fixed-variable rate designs are used to allow for recovery of substantially all fixed costs in demand or reservation charges, thereby reducing the earnings impact of volume changes on gas transportation and storage operations.

MountainWest receives upfront payment for certain storage services it provides to customers, which are considered to be contract liabilities. These payments are amortized to revenue over the term of the contract.

The primary types of sales and service activities reported as revenue from contracts with customers are FERC-regulated gas transportation and storage services, and to a lesser extent, natural gas liquid (“NGL”) revenues consisting primarily of NGL processing services, and other revenue (consisting of natural gas sales, as well as services related to gathering and processing activities and miscellaneous service revenue).

Transportation and storage contracts are primarily stand-ready service contracts that include fixed reservation and variable usage fees. Fixed fees are recognized ratably over the life of the contract as the stand-ready performance obligations are satisfied, while variable usage fees are recognized when MountainWest has a right to consideration from a customer in an amount that corresponds directly with the value to the customer of the performance obligation completed to date. Substantially all of MountainWest’s revenues are derived from performance obligations satisfied over time, rather than recognized at a single point in time. Payment for most sales and services varies by contract type, but is typically due within a month of billing.

MountainWest typically receives or retains NGLs and natural gas from customers when providing natural gas processing, transportation, or storage services. MountainWest records the fair value of NGLs received as service revenue recognized over time and recognizes revenue from the subsequent sale of the NGLs to customers upon delivery. MountainWest typically retains some natural gas under certain transportation service arrangements, intended to facilitate performance of the service and allow for natural losses that occur. As the intent of the retention amount is to enable fulfillment of the contract rather than to provide compensation for services, the fuel allowance is not included in revenue.

MountainWest Regulated operations revenues on the Condensed Consolidated Statements of Income of the Company include revenue from contracts with customers, which is shown below, disaggregated by categories of sales and service activities.


	Three Months Ended June 30,		Six Months Ended June 30,
(Thousands of dollars)	2022
Regulated gas transportation and storage revenues	$	57,786	119,763
NGL revenues	1,876		3,369
Other revenues	2,380		5,859
Revenue from contracts with customers	62,042		128,991
Other revenues	46		90
Total Regulated operations revenues	$	62,088	129,081

MountainWest has certain multi-year contracts with fixed-price performance obligations that were unsatisfied (or partially unsatisfied) at the end of the reporting period, whereby revenue will be earned over time as MountainWest stands ready to provide service. These amounts are not material to the Company’s financial statements overall. MountainWest also has certain contract liabilities related to consideration received from customers with an obligation to transfer goods or services subsequent to the balance sheet date, amounts for which are generally consistent between December 31, 2021 and June 30, 2022 and are not material.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI https://asc.fasb.org/topic&trid=49130388

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+ Details

Common Stock

6 Months Ended

Jun. 30, 2022

Equity [Abstract]

Common Stock

Note 4 – Common Stock

Shares of the Company’s common stock are publicly traded on the New York Stock Exchange, under the ticker symbol “SWX.” Share-based compensation related to Southwest and Centuri is based on stock awards to be issued in shares of Southwest Gas Holdings, Inc.

On April 8, 2021, the Company entered into a Sales Agency Agreement between the Company and BNY Mellon Capital Markets, LLC and J.P. Morgan Securities LLC (the “Equity Shelf Program”) for the offer and sale of up to $500 million of common stock from time to time in an at-the-market offering program. The shares are issued pursuant to the Company’s automatic shelf registration statement on Form S-3 (File No. 333-251074), or “the Universal Shelf.” There was no activity under the Equity Shelf Program during the quarter ended June 30, 2022. The following table provides the life-to-date activity under that program through June 30, 2022:




Gross proceeds	$	158,180,343
Less: agent commissions	(1,581,803)
Net proceeds	$	156,598,540
Number of shares sold	2,302,407
Weighted average price per share	$	68.70

As of June 30, 2022, the Company had approximately $341.8 million in common stock available for sale under the program.

In March 2022, the Company issued, through a separate prospectus supplement under the Universal Shelf, an aggregate of 6.325 million shares of common stock, in an underwritten public offering price of $74.00 per share, resulting in proceeds to the Company of $452.3 million, net of an underwriters’ discount of $15.8 million. The Company used the net proceeds to repay a portion of the outstanding borrowings under the 364-day term loan credit agreement that was used to initially fund the MountainWest acquisition.

During the six months ended June 30, 2022, the Company issued approximately 191,000 shares of common stock through the Restricted Stock/Unit Plan and Omnibus Incentive Plan.

Additionally, during the six months ended June 30, 2022, the Company issued 66,000 shares of common stock through the Dividend Reinvestment and Stock Purchase Plan, raising approximately $5.1 million.

In connection with the entry into the Cooperation Agreement (see Note 1 – Background, Organization, and Summary of Significant Accounting Policies), the Company entered into the Amended Rights Agreement to increase the beneficial ownership percentage included in the definition of “Acquiring Person” from 10% to 24.9% and to delete the concept of a “Passive Institutional Investor” to permit the Icahn Group to consummate the Offer.

Debt

6 Months Ended

Jun. 30, 2022

Debt Disclosure [Abstract]

Debt

Note 5 – Debt

Long-Term Debt

Long-term debt is recognized in the Company’s and Southwest’s Condensed Consolidated Balance Sheets generally at the carrying value of the obligations outstanding. Details surrounding the fair value and individual carrying values of instruments are provided in the table that follows.


	June 30, 2022				December 31, 2021
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
(Thousands of dollars)
Southwest Gas Corporation:
Debentures:
Notes, 6.1%, due 2041	$	125,000	$	126,410	$	125,000	$	166,380
Notes, 4.05%, due 2032	600,000		549,396		—		—
Notes, 3.875%, due 2022	—		—		250,000		250,603
Notes, 4.875%, due 2043	250,000		230,653		250,000		307,538
Notes, 3.8%, due 2046	300,000		235,140		300,000		329,055
Notes, 3.7%, due 2028	300,000		283,260		300,000		325,191
Notes, 4.15%, due 2049	300,000		250,461		300,000		342,030
Notes, 2.2%, due 2030	450,000		365,054		450,000		440,838
Notes, 3.18%, due 2051	300,000		211,326		300,000		292,116
8% Series, due 2026	75,000		84,078		75,000		92,623
Medium-term notes, 7.78% series, due 2022	—		—		25,000		25,122
Medium-term notes, 7.92% series, due 2027	25,000		27,821		25,000		31,555
Medium-term notes, 6.76% series, due 2027	7,500		7,839		7,500		8,949
Unamortized discount and debt issuance costs	(26,627)				(19,959)
	2,705,873				2,387,541
Revolving credit facility and commercial paper	—		—		130,000		130,000
Industrial development revenue bonds:
Tax-exempt Series A, due 2028	50,000		50,000		50,000		50,000
2003 Series A, due 2038	50,000		50,000		50,000		50,000
2008 Series A, due 2038	50,000		50,000		50,000		50,000
2009 Series A, due 2039	50,000		50,000		50,000		50,000
Unamortized discount and debt issuance costs	(1,774)				(1,938)
	198,226				198,062
Less: current maturities	—				(275,000)
Southwest Gas Corporation total long-term debt, less current maturities	$	2,904,099			$	2,440,603
Southwest Gas Holdings, Inc.:
Centuri secured term loan facility	$	1,011,413	$	970,329	$	1,117,138	$	1,117,841
Centuri secured revolving credit facility	145,885		145,759		103,329		103,749
MountainWest unsecured senior notes, 3.53%, due in 2028	101,922		90,430		102,078		102,078
MountainWest unsecured senior notes, 4.875%, due in 2041	199,599		157,894		199,926		199,926
MountainWest unsecured senior notes, 3.91%, due in 2038	147,786		113,703		147,735		147,735
Other debt obligations	141,653		129,810		51,665		50,003
Unamortized discount and debt issuance costs	(22,627)				(24,466)
Less: current maturities	(41,276)				(22,324)
Southwest Gas Holdings, Inc. total long-term debt, less current maturities	$	4,588,454			$	4,115,684

Southwest has a $400 million credit facility that is scheduled to expire in April 2025. Southwest designates $150 million of associated capacity as long-term debt and the remaining $250 million for working capital purposes. Interest rates for the credit facility are calculated at either the Secured Overnight Financing Rate (“SOFR”) or an “alternate base rate,” plus in each case an applicable margin that is determined based on Southwest’s senior unsecured debt rating. At June 30, 2022, the applicable margin is 1.125% for loans bearing interest with reference to SOFR and 0.125% for loans bearing interest with reference to the alternative base rate. At June 30, 2022, no borrowings were outstanding on the long-term portion of the facility (including under the commercial paper program, discussed below), nor on the short-term portion of the facility.

Southwest has a $50 million commercial paper program. Issuances under the commercial paper program are supported by Southwest’s revolving credit facility and, therefore, do not represent additional borrowing capacity under the credit facility. Borrowings under the commercial paper program, if any, are designated as long-term debt. Interest rates for the program are calculated at the then current commercial paper rate. At June 30, 2022, as noted above, no borrowings were outstanding under the commercial paper program.

In March 2022, Southwest issued $600 million aggregate principal amount of 4.05% Senior Notes at a discount of 0.65%. The notes will mature in March 2032. Southwest used the net proceeds to redeem the $250 million 3.875% notes due in April 2022 and to repay outstanding amounts under its credit facility, with the remaining net proceeds used for general corporate purposes.

Centuri has a $1.545 billion secured revolving credit and term loan multi-currency facility. Amounts can be borrowed in either Canadian or U.S. dollars. The revolving credit facility matures on August 27, 2026 and the term loan facility matures on August 27, 2028. Interest rates for the revolving credit facility and term loan facility are based on either a “base rate” or LIBOR, plus an applicable margin in either case. The capacity of the line of credit portion of the facility is $400 million; related amounts borrowed and repaid are available to be re-borrowed. The term loan portion of the facility has a limit of $1.145 billion. The obligations under the credit agreement are secured by present and future ownership interests in substantially all direct and indirect subsidiaries of Centuri, substantially all of the tangible and intangible personal property of each borrower, certain of their direct and indirect subsidiaries, and all products, profits, and proceeds of the foregoing. Centuri’s assets securing the facility at June 30, 2022 totaled $2.5 billion. At June 30, 2022, $1.157 billion in borrowings were outstanding under Centuri’s combined secured revolving credit and term loan facility.

MountainWest has two private placement unsecured senior notes and a public unsecured senior note, with a combined carrying value of $449.3 million and aggregate principal amount of $430 million. The carrying value is higher than the principal balance as amounts outstanding were recorded at their fair values as of the December 31, 2021 acquisition date of the MountainWest entities.

Short-Term Debt

Southwest Gas Holdings, Inc. has a $200 million credit facility that is scheduled to expire in December 2026 and is primarily used for short-term financing needs. Interest rates for the credit facility are calculated at either SOFR or the “alternate base rate” plus in each case an applicable margin. There was $90 million outstanding under this credit facility as of June 30, 2022.

As indicated above, under Southwest’s $400 million credit facility, no short-term borrowings were outstanding at June 30, 2022.

In March 2022, Southwest amended its $250 million Term Loan (the “March 2021 Term Loan”), extending the maturity date to March 21, 2023 and replacing LIBOR interest rate benchmarks with SOFR interest rate benchmarks. The proceeds were originally used to fund the increased cost of natural gas supply during the month of February 2021, caused by extreme weather conditions in the central U.S. There was $225 million outstanding under the March 2021 Term Loan as of June 30, 2022.

In November 2021, Southwest Gas Holdings, Inc. entered into a 364-day term loan credit agreement (the “Credit Agreement”). The Credit Agreement provided for a $1.6 billion delayed-draw term loan (the “Term Loan Facility”) to primarily fund the acquisition of the equity interests in MountainWest (refer to Note 8 - Business Acquisitions). The Term Loan Facility was funded on December 31, 2021, and matures on December 30, 2022. There was $1.15 billion outstanding under the Term Loan Facility as of June 30, 2022.

The borrowings under the Term Loan Facility created a negative working capital condition for the Company, which as of June 30, 2022 is approximately $707 million. As of August 9, 2022, the Company does not have sufficient liquidity or capital resources to repay the Term Loan Facility without issuing new debt or equity. As disclosed in Note 1 – Background, Organization, and Summary of Significant Accounting Policies, the Company is exploring strategic alternatives, including a potential sale of MountainWest. Management intends to either issue long-term debt to refinance the Term Loan Facility or extend the Term Loan Facility up to 364 days. If MountainWest is sold as part of the Strategic Review process, the proceeds will be used to repay the amounts borrowed to fund the acquisition.

Management believes that its refinancing plan is probable based on the Company’s ability to generate consistent cash flows, its current credit ratings, its relationships with its lenders and its prior history of successfully raising debt and equity necessary to fund its acquisitions and operations. As such, management has concluded that the Company can satisfy its obligations for at least the next twelve months from the issuance date of these financial statements.

The Company’s ability to access capital markets or to otherwise obtain sufficient financing may be affected by future conditions. If the Company is unable to execute its plan to refinance debt obligations, the Company’s credit facility could be terminated, and amounts due under its revolver and other borrowing arrangements could be declared immediately due and payable.

LIBOR

Certain rates established at LIBOR are scheduled to be discontinued as a benchmark or reference rate after 2021, while other LIBOR-based rates are scheduled to be discontinued after June 2023. As of June 30, 2022, the Company had $2.16 billion in aggregate outstanding borrowings under Centuri’s combined facility and Southwest Gas Holdings, Inc.’s Term Loan Facility. Southwest had no outstanding borrowings or variable rate debt agreements with reference to LIBOR as of June 30, 2022. In order to mitigate the impact on the financial condition and results of operations of the Company, management will monitor developments and work with lenders to determine the appropriate replacement/alternative reference rate for variable rate debt. At this time the Company can provide no assurances as to the impact a LIBOR discontinuance will have on its financial condition or results of operations. Any alternative rate may be less predictable or less attractive than LIBOR.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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+ Details

Other Comprehensive Income and Accumulated Other Comprehensive Income

6 Months Ended

Jun. 30, 2022

Equity [Abstract]

Other Comprehensive Income and Accumulated Other Comprehensive Income

Note 6 – Other Comprehensive Income and Accumulated Other Comprehensive Income

The following information presents the Company’s Other comprehensive income (loss), both before and after-tax impacts, within the Condensed Consolidated Statements of Comprehensive Income, which also impact Accumulated other comprehensive income (“AOCI”) in the Condensed Consolidated Balance Sheets and the Condensed Consolidated Statements of Equity.

Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss)


	Three Months Ended June 30, 2022						Three Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Amortization of prior service cost	$	44	$	(11)	$	33	$	240	$	(58)	$	182
Amortization of net actuarial (gain)/loss	8,704		(2,089)		6,615		11,148		(2,676)		8,472
Regulatory adjustment	(7,268)		1,744		(5,524)		(9,575)		2,298		(7,277)
Pension plans other comprehensive income (loss)	1,480		(356)		1,124		1,813		(436)		1,377
FSIRS (designated hedging activities):
Amounts reclassified into net income	—		—		—		544		(130)		414
FSIRS other comprehensive income (loss)	—		—		—		544		(130)		414
Total other comprehensive income (loss) - Southwest Gas Corporation	1,480		(356)		1,124		2,357		(566)		1,791
Foreign currency translation adjustments:
Translation adjustments	(2,680)		—		(2,680)		909		—		909
Foreign currency other comprehensive income (loss)	(2,680)		—		(2,680)		909		—		909
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	(1,200)	$	(356)	$	(1,556)	$	3,266	$	(566)	$	2,700

	Six Months Ended June 30, 2022						Six Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Amortization of prior service cost	$	88	$	(22)	$	66	$	480	$	(116)	$	364
Amortization of net actuarial (gain)/loss	17,409		(4,178)		13,231		22,297		(5,351)		16,946
Regulatory adjustment	(14,536)		3,489		(11,047)		(19,150)		4,596		(14,554)
Pension plans other comprehensive income (loss)	2,961		(711)		2,250		3,627		(871)		2,756
FSIRS (designated hedging activities):
Amounts reclassified into net income	545		(129)		416		1,088		(261)		827
FSIRS other comprehensive income (loss)	545		(129)		416		1,088		(261)		827
Total other comprehensive income (loss) - Southwest Gas Corporation	3,506		(840)		2,666		4,715		(1,132)		3,583
Foreign currency translation adjustments:
Translation adjustments	(1,433)		—		(1,433)		1,732		—		1,732
Foreign currency other comprehensive income (loss)	(1,433)		—		(1,433)		1,732		—		1,732
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	2,073	$	(840)	$	1,233	$	6,447	$	(1,132)	$	5,315


	Twelve Months Ended June 30, 2022						Twelve Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Net actuarial gain/(loss)	$	59,176	$	(14,202)	$	44,974	$	(57,539)	$	13,809	$	(43,730)
Amortization of prior service cost	567		(136)		431		1,057		(255)		802
Amortization of net actuarial (gain)/loss	39,709		(9,530)		30,179		41,212		(9,890)		31,322

Regulatory adjustment	(83,580)		20,060		(63,520)		5,075		(1,219)		3,856
Pension plans other comprehensive income (loss)	15,872		(3,808)		12,064		(10,195)		2,445		(7,750)
FSIRS (designated hedging activities):
Amounts reclassified into net income	1,631		(390)		1,241		2,662		(639)		2,023
FSIRS other comprehensive income (loss)	1,631		(390)		1,241		2,662		(639)		2,023
Total other comprehensive income (loss) - Southwest Gas Corporation	17,503		(4,198)		13,305		(7,533)		1,806		(5,727)
Foreign currency translation adjustments:
Translation adjustments	(3,145)		—		(3,145)		5,656		—		5,656
Foreign currency other comprehensive income (loss)	(3,145)		—		(3,145)		5,656		—		5,656
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	14,358	$	(4,198)	$	10,160	$	(1,877)	$	1,806	$	(71)

(1)Tax amounts are calculated using a 24% rate. The Company has elected to indefinitely reinvest, in Canada, the earnings of Centuri’s Canadian subsidiaries, thus precluding deferred taxes on such earnings. As a result of this assertion, and no repatriation of earnings anticipated, the Company is not recognizing a tax effect or presenting a tax expense or benefit for currency translation adjustments reported in Other comprehensive income (loss).

The following table represents a rollforward of AOCI, presented on the Company’s Condensed Consolidated Balance Sheets and its Condensed Consolidated Statements of Equity:


	Defined Benefit Plans						FSIRS						Foreign Currency Items
(Thousands of dollars)	Before-Tax		Tax (Expense) Benefit (4)		After-Tax		Before-Tax		Tax (Expense) Benefit (4)		After-Tax		Before-Tax		Tax (Expense) Benefit		After-Tax		AOCI
Beginning Balance AOCI December 31, 2021	$	(61,182)	$	14,685	$	(46,497)	$	(545)	$	129	$	(416)	$	152	$	—	$	152	$	(46,761)
Translation adjustments	—		—		—		—		—		—		(1,433)		—		(1,433)		(1,433)
Other comprehensive income (loss) before reclassifications	—		—		—		—		—		—		(1,433)		—		(1,433)		(1,433)
FSIRS amount reclassified from AOCI (1)	—		—		—		545		(129)		416		—		—		—		416
Amortization of prior service cost (2)	88		(22)		66		—		—		—		—		—		—		66
Amortization of net actuarial loss (2)	17,409		(4,178)		13,231		—		—		—		—		—		—		13,231
Regulatory adjustment (3)	(14,536)		3,489		(11,047)		—		—		—		—		—		—		(11,047)
Net current period other comprehensive income (loss) attributable to Southwest Gas Holdings, Inc.	2,961		(711)		2,250		545		(129)		416		(1,433)		—		(1,433)		1,233
Ending Balance AOCI June 30, 2022	$	(58,221)	$	13,974	$	(44,247)	$	—	$	—	$	—	$	(1,281)	$	—	$	(1,281)	$	(45,528)

(1)The FSIRS reclassification amount is included in Net interest deductions on the Company’s Condensed Consolidated Statements of Income.

(2)These AOCI components are included in the computation of net periodic benefit cost (see Note 2 – Components of Net Periodic Benefit Cost for additional details).

(3)The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in Deferred charges and other assets on the Company’s Condensed Consolidated Balance Sheets).

(4)Tax amounts are calculated using a 24% rate.

The following table represents a rollforward of AOCI, presented on Southwest’s Condensed Consolidated Balance Sheets:


	Defined Benefit Plans						FSIRS
(Thousands of dollars)	Before-Tax		Tax (Expense) Benefit (8)		After-Tax		Before-Tax		Tax (Expense) Benefit (8)		After-Tax		AOCI
Beginning Balance AOCI December 31, 2021	$	(61,182)	$	14,685	$	(46,497)	$	(545)	$	129	$	(416)	$	(46,913)
FSIRS amount reclassified from AOCI (5)	—		—		—		545		(129)		416		416
Amortization of prior service cost (6)	88		(22)		66		—		—		—		66
Amortization of net actuarial loss (6)	17,409		(4,178)		13,231		—		—		—		13,231
Regulatory adjustment (7)	(14,536)		3,489		(11,047)		—		—		—		(11,047)
Net current period other comprehensive income attributable to Southwest Gas Corporation	2,961		(711)		2,250		545		(129)		416		2,666
Ending Balance AOCI June 30, 2022	$	(58,221)	$	13,974	$	(44,247)	$	—	$	—	$	—	$	(44,247)

(5) The FSIRS reclassification amount is included in Net interest deductions on Southwest’s Condensed Consolidated Statements of Income.

(6)These AOCI components are included in the computation of net periodic benefit cost (see Note 2 – Components of Net Periodic Benefit Cost for additional details).

(7)The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in Deferred charges and other assets on Southwest’s Condensed Consolidated Balance Sheets).

(8)Tax amounts are calculated using a 24% rate.

The following table represents amounts (before income tax impacts) included in AOCI (in the tables above), that have not yet been recognized in net periodic benefit cost:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Net actuarial loss	$	(381,601)	$	(399,010)
Prior service cost	(1,440)		(1,528)
Less: amount recognized in regulatory assets	324,820		339,356
Recognized in AOCI	$	(58,221)	$	(61,182)

Segment Information

6 Months Ended

Jun. 30, 2022

Segment Reporting [Abstract]

Segment Information

Note 7 – Segment Information

As a result of the MountainWest acquisition on December 31, 2021, management updated its segment reporting from the historical presentation of two reportable segments to three reportable segments, with MountainWest presented as the pipeline and storage segment. Southwest comprises the natural gas distribution segment and Centuri comprises the utility infrastructure services segment.

Centuri accounts for the services provided to Southwest at contractual prices. Accounts receivable for these services, which are not eliminated during consolidation, are presented in the table below:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Centuri accounts receivable for services provided to Southwest	$	16,915	$	15,166

In order to reconcile (below) to net income as disclosed in the Condensed Consolidated Statements of Income, an Other column is included associated with impacts of corporate and administrative activities related to Southwest Gas Holdings, Inc. The financial information pertaining to the natural gas distribution, utility infrastructure services, and pipeline and storage segments are as follows:


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Three Months Ended June 30, 2022
Revenues from external customers	$	377,942	$	672,119	$	62,088	$	—	$	1,112,149
Intersegment revenues	—		33,971		—		—		33,971
Total	$	377,942	$	706,090	$	62,088	$	—	$	1,146,120
Segment net income (loss)	$	(2,266)	$	4,741	$	15,076	$	(24,126)	$	(6,575)

Three Months Ended June 30, 2021
Revenues from external customers	$	292,796	$	504,941	$	—	$	—	$	797,737
Intersegment revenues	—		23,684		—		—		23,684
Total	$	292,796	$	528,625	$	—	$	—	$	821,421
Segment net income (loss)	$	11,413	$	15,116	$	—	$	(1,410)	$	25,119

(Thousands of dollars)	Natural Gas Operations		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Six Months Ended June 30, 2022
Revenues from external customers	$	1,054,481	$	1,167,663	$	129,081	$	—	$	2,351,225
Intersegment revenues	—		62,304		—		—		62,304
Total	$	1,054,481	$	1,229,967	$	129,081	$	—	$	2,413,529
Segment net income (loss)	$	109,529	$	(18,745)	$	32,006	$	(33,187)	$	89,603

Six Months Ended June 30, 2021
Revenues from external customers	$	814,728	$	844,713	$	—	$	—	$	1,659,441
Intersegment revenues	—		47,887		—		—		47,887
Total	$	814,728	$	892,600	$	—	$	—	$	1,707,328
Segment net income (loss)	$	130,128	$	14,257	$	—	$	(1,973)	$	142,412


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Twelve Months Ended June 30, 2022
Revenues from external customers	$	1,761,543	$	2,379,265	$	129,081	$	—	$	4,269,889
Intersegment revenues	—		116,763		—		—		116,763
Total	$	1,761,543	$	2,496,028	$	129,081	$	—	$	4,386,652
Segment net income (loss)	$	166,536	$	7,418	$	32,006	$	(57,990)	$	147,970

Twelve Months Ended June 30, 2021
Revenues from external customers	$	1,400,052	$	1,899,961	$	—	$	—	$	3,300,013
Intersegment revenues	—		112,621		—		—		112,621
Total	$	1,400,052	$	2,012,582	$	—	$	—	$	3,412,634
Segment net income (loss)	$	193,705	$	73,056	$	—	$	(2,532)	$	264,229

The corporate and administrative activities for Southwest Gas Holdings, Inc. in the three-, six-, and twelve-month periods ended June 30, 2022 include expenses incurred related to shareholder activism and related settlement activities, expenses incurred in conducting the Strategic Review, and expenses and financing costs for the MountainWest acquisition.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8721-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9031-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9038-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 32
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8657-108599

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8721-108599

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-URI https://asc.fasb.org/topic&trid=2134510

+ Details

Business Acquisitions

6 Months Ended

Jun. 30, 2022

Business Combination and Asset Acquisition [Abstract]

Business Acquisitions

Note 8 - Business Acquisitions

In August 2021, the Company, through its subsidiaries, led principally by Centuri, completed the acquisition of Drum, including its primary subsidiary, Riggs Distler. In November 2021, certain members of Riggs Distler management acquired a 1.42% interest in Drum. See the Company’s 2021 Form 10-K for additional information about this acquisition.

Assets acquired and liabilities assumed in the transaction were recorded at their acquisition date fair values. Transaction costs associated with the acquisition were expensed as incurred. The Company’s allocation of the purchase price was based on an evaluation of the appropriate fair values and represented management’s best estimate based on available data (including market data, data regarding customers of the acquired businesses, terms of acquisition-related agreements, analysis of historical and projected results, and other types of data). The analysis included consideration of types of intangibles that were acquired, including customer relationships, trade name, and backlog. Certain payments were estimated as of the acquisition date and were adjusted when amounts were finalized. Further adjustments may still occur. Due to the estimations made, the final purchase accounting has not yet been completed and further refinements may occur, including potential changes to income taxes.

The preliminary estimated fair values of assets acquired and liabilities assumed as of August 27, 2021, and as updated through June 30, 2022, are as follows:


(Millions of dollars)	Acquisition Date		Measurement Period Adjustments		Revised Acquisition Date
Cash and cash equivalents	$	1.9	$	—	$	1.9
Accounts receivable	69.1		(8.6)		60.5
Contract assets	40.1		7.4		47.5
Income taxes receivable, net	0.7		—		0.7
Right of use assets under operating leases	1.5		—		1.5
Prepaid expenses	5.2		—		5.2
Property and equipment	118.1		1.2		119.3
Intangible assets	335.0		(31.5)		303.5
Goodwill	446.8		1.8		448.6
Total assets acquired	1,018.4		$	(29.7)	$	988.7

Trade and other payables	46.2		—		46.2
Finance lease obligations	27.5		1.2		28.7
Contract liabilities	12.7		—		12.7
Operating lease obligations	1.5		—		1.5
Other liabilities	5.3		(1.2)		4.1
Deferred tax liabilities	94.8		(23.4)		71.4
Total liabilities assumed and noncontrolling interest	188.0		(23.4)		164.6
Net assets acquired	$	830.4	$	(6.3)	$	824.1

The Company incurred and expensed acquisition costs of $14 million, included in Utility infrastructure services expenses in the Company’s Condensed Consolidated Statement of Income for the twelve months ended June 30, 2022. No acquisition-related costs were incurred during the three and six months ended June 30, 2022, and no significant impacts to earnings resulted from the measurement-period adjustments reflected above.

In December 2021 Southwest Gas Holdings, Inc. completed the acquisition of Dominion Energy Questar Pipeline, LLC and related entities (subsequently rebranded as “MountainWest”), which resulted in MountainWest becoming a wholly owned subsidiary of the Company. See the Company’s 2021 Form 10-K for additional information about this acquisition.

Assets acquired and liabilities assumed in the transaction were recorded at their acquisition date fair values. Transaction costs associated with the acquisition were expensed as incurred. The majority of the operations acquired are subject to FERC rate-regulation and therefore are accounted for pursuant to ASC 980, Regulated Operations. The fair values of MountainWest’s

assets and liabilities, subject to rate making and cost recovery provisions, provide revenues derived from costs of service, including a return on investment of assets and liabilities included in rate base. Accordingly, the carrying values of such assets and liabilities were deemed to approximate their fair values. The fair value of the MountainWest assets and liabilities assumed that are not subject to the rate-regulation provisions discussed above include a 50% equity method investment, non-regulated property, plant and equipment, and long-term debt assumed; related fair values were determined using a market approach, income approach, or cost approach, as appropriate. Amounts related to post-closing payments and deferred taxes were estimated as of the acquisition date and adjusted when determined during the period ended June 30, 2022. No other measurement period adjustments occurred during the period. However, the final purchase accounting has not yet been completed and further refinements may occur, including finalization of income tax-related amounts.

The preliminary estimated fair values of assets acquired and liabilities assumed as of December 31, 2021, and as updated through June 30, 2022, are as follows:


(Millions of dollars)	Acquisition Date		Measurement Period Adjustments		Revised Acquisition Date
Gas plant, net	$	1,047.4	$	—	$	1,047.4
Other property and investments	51.3		—		51.3
Cash and cash equivalents	17.6		—		17.6
Accounts receivable, net of allowances	26.6		2.9		29.5
Prepaid and other current assets	27.4		—		27.4
Deferred charges and other assets	31.1		—		31.1
Goodwill	986.2		(28.2)		958.0
Deferred income taxes, net	15.4		20.9		36.3
Total assets acquired	2,203.0		(4.4)		2,198.6

Long-term debt	449.7		—		449.7
Accounts payable	7.0		—		7.0
Deferred purchased gas costs	5.7		—		5.7
Customer deposits	3.2		—		3.2
Accrued general taxes	0.4		—		0.4
Accrued interest	4.7		—		4.7
Other current liabilities	14.5		—		14.5
Accumulated removal costs	56.6		—		56.6
Other deferred credits	85.6		—		85.6
Total liabilities assumed	627.4		—		627.4
Net assets acquired	$	1,575.6	$	(4.4)	$	1,571.2

The Company incurred and expensed acquisition costs of $18.5 million for the twelve months ended June 30, 2022, which are included in Operations and maintenance expense on the Company’s Condensed Consolidated Statement of Income. No acquisition-related costs were incurred during the six months ended June 30, 2022 and no impacts to earnings resulted from the measurement-period adjustments reflected above. The Company has a transition services agreement with the sellers for a period of up to twelve months from the acquisition date of December 31, 2021, to continue certain corporate and administrative functions for the entities acquired while MountainWest is established as an independent enterprise.

Background, Organization, and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations. Southwest Gas Holdings, Inc. (together with its subsidiaries, the “Company”) is a holding company, owning all of the shares of common stock of Southwest Gas Corporation (“Southwest” or the “natural gas distribution” segment), all of the shares of common stock of Centuri Group, Inc. (“Centuri,” or the “utility infrastructure services” segment), and all of the shares of common stock of MountainWest Pipelines Holding Company (“MountainWest,” or the “pipeline and storage” segment). The Company completed the acquisition of Dominion Energy Questar Pipeline, LLC and related entities (“Questar Pipelines”) in December 2021. Following the completion of the acquisition, the Company formed MountainWest which owns all of the membership interests in Questar Pipelines. In April 2022, the Company completed a general rebranding of the Questar Pipelines entities under the MountainWest name. The acquired operations further diversify the Company’s business in the midstream sector, with an expansion of interstate natural gas pipelines and underground storage services, primarily composed of regulated operations under the jurisdiction of the Federal Energy Regulatory Commission (the “FERC”), thereby expanding natural gas transportation services into Utah, Wyoming, and Colorado. See Note 8 - Business Acquisitions for more information. Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. Results for the natural gas distribution segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures. Centuri is a strategic utility infrastructure services company dedicated to partnering with North America’s gas and electric providers to build and maintain the energy network that powers millions of homes across the United States (“U.S.”) and Canada. Centuri derives revenue primarily from installation, replacement, repair, and maintenance of energy networks. Centuri operates in the U.S., primarily as NPL, Neuco, Linetec, and Riggs Distler, and in Canada, primarily as NPL Canada. Utility infrastructure services activity is seasonal in many of Centuri’s operating areas. Peak periods are the summer and fall months in colder climate areas, such as the northeastern and midwestern U.S. and in Canada. In warmer climate areas, such as the southwestern and southeastern U.S., utility infrastructure services activity continues year round.
Basis of Presentation	Basis of Presentation. The condensed consolidated financial statements of Southwest Gas Holdings, Inc. and subsidiaries and Southwest included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). The year-end 2021 condensed balance sheet data was derived from audited financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. No substantive change has occurred with regard to the Company’s business segments on the whole during the recently completed quarter. The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments, consisting of normal recurring items and estimates necessary for a fair depiction of results for the interim periods, have been made. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the 2021 Annual Report to Stockholders, which is incorporated by reference into the 2021 Form 10-K.
Cash and Cash Equivalents	Cash and Cash Equivalents. Cash and cash equivalents include money market fund investments totaling approximately $77 million and $97 million, for Southwest and the Company, respectively, at June 30, 2022, and $20 million for the Company as of December 31, 2021. The balance for Southwest as of December 31, 2021 was insignificant. These investments fall within Level 2 of the fair value hierarchy, due to the asset valuation methods used by money market funds. Non-cash investing activities for the Company and Southwest include capital expenditures that were not yet paid, thereby remaining in accounts payable, which declined by approximately $11.6 million and $18.3 million, respectively, during the six months ended June 30, 2022, and increased $6.5 million and $6.6 million, respectively, during the twelve months ended June 30, 2022.
Accounts Receivable, net of allowances	Accounts Receivable, net of allowances. Following an earlier moratorium on account disconnections amidst the COVID-19 environment, account collection efforts resumed in 2021 in all jurisdictions in which Southwest operates. Ultimately, some accounts may not be collected, and if so, would be written off. Estimates as to collectibility are made on an ongoing basis. However, Southwest continues to actively work with customers experiencing financial hardship by means of flexible payment options and partnering with assistance agencies. The cost of gas included in customer rates also influences account balances at each reporting date.
Deferred Purchased Gas Costs	Deferred Purchased Gas Costs. The various regulatory commissions have established procedures to enable the rate-regulated companies to adjust billing rates for changes in the cost of natural gas purchased. The difference between the current cost of gas purchased and the cost of gas recovered in billed rates is deferred. Generally, these deferred amounts are recovered or refunded within one year.
Prepaid and other current assets	Prepaid and other current assets. Prepaid and other current assets for Southwest include, among other things, materials and operating supplies of $70.2 million at June 30, 2022 and $62.9 million at December 31, 2021 (carried at weighted average cost). For the Company, there were materials and operating supplies of $74.5 million and $67.4 million at June 30, 2022 and December 31, 2021, respectively, which included amounts for MountainWest. Also included in the balance for both Southwest and the Company was $10.2 million and $52 million as of June 30, 2022 and December 31, 2021, respectively, in accrued purchased gas cost.
Goodwill	Goodwill. Goodwill is assessed as of October 1st each year for impairment, or more frequently, if circumstances indicate an impairment to the carrying value of goodwill may have occurred. Management of the Company and Southwest considered its reporting units and segments, determining that they remained consistent between periods presented below, and that no change was necessary with regard to the level at which goodwill is assessed for impairment. The acquisition of MountainWest resulted in a new reportable segment which is assessed for impairment beginning in 2022.
Other Current Liabilities	Other Current Liabilities. Management recognizes in its balance sheets various liabilities that are expected to be settled through future cash payment within the next twelve months, including amounts payable under regulatory mechanisms, customary accrued expenses for employee compensation and benefits, declared but unpaid dividends, and miscellaneous other accrued liabilities. Other current liabilities for the Company include $41.5 million and $36 million of dividends declared as of June 30, 2022 and December 31, 2021, respectively.
Earnings Per Share	Earnings Per Share. Basic earnings per share (“EPS”) in each period of this report were calculated by dividing net income attributable to Southwest Gas Holdings, Inc. by the weighted-average number of shares during those periods. Diluted EPS includes additional weighted-average common stock equivalents (performance shares and restricted stock units). Unless otherwise noted, the term “Earnings Per Share” refers to Basic EPS.
Recent Accounting Standards Updates	Recent Accounting Standards Updates. Accounting pronouncements effective or adopted in 2022: In March 2020, the Financial Accounting Standards Board (the “FASB”) issued ASU 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” The update provides optional guidance for a limited time to ease the potential burden in accounting for, or recognizing the effects of, reference rate reform on financial reporting, including when modifying a contract (during the eligibility period covered by the update to Topic 848) to replace a reference rate affected by such reform. The update applies only to contracts and hedging relationships that reference the London Interbank Offered Rate (“LIBOR”) or another rate expected to be discontinued due to reference rate reform. The guidance was eligible to be applied upon issuance on March 12, 2020, and can generally be applied through December 31, 2022, and while a proposal by the FASB has occurred to extend the optional guidance to the full tenor of LIBOR expiration dates occurring after 2022, to date, no such update has been made effective. Management will monitor the impacts this update might have on the Company’s and Southwest’s consolidated financial statements and disclosures, and will reflect such appropriately, in the event that the optional guidance is elected. Management will also monitor further FASB action, if any, in regard to the full tenor of LIBOR expiration dates.In August 2020, the FASB issued ASU 2020-06 “Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity.” The update, amongst other amendments, improves the guidance related to the disclosures and earnings-per-share for convertible instruments and contracts in an entity’s own equity. The Company and Southwest adopted the update in the first quarter of 2022, the impact of which was not material to the consolidated financial statements of the Company or Southwest.

Background, Organization, and Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Other Property and Investments

Other property and investments on Southwest’s and the Company’s Condensed Consolidated Balance Sheets includes:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Net cash surrender value of COLI policies	$	142,819	$	149,947
Other property	3,780		3,146
Total Southwest Gas Corporation	146,599		153,093
Non-regulated property, equipment, and intangibles	1,678,683		1,616,392
Non-regulated accumulated provision for depreciation and amortization	(569,630)		(512,343)
Other property and investments	57,049		59,337
Total Southwest Gas Holdings, Inc.	$	1,312,701	$	1,316,479

Schedule of Goodwill

Goodwill in the Natural Gas Distribution operations of Southwest, and across all operations of the Company, is included in their respective Condensed Consolidated Balance Sheets as follows:


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Total Company
December 31, 2021	$	10,095	$	785,058	$	986,179	$	1,781,332
Measurement-period adjustments from Riggs Distler acquisition (a)	—		(906)				(906)
Measurement-period adjustments from MountainWest acquisition (a)	—		—		(28,178)		(28,178)
Foreign currency translation adjustment	—		(1,776)		—		(1,776)
June 30, 2022	$	10,095	$	782,376	$	958,001	$	1,750,472

(a) See Note 8 - Business Acquisitions for details regarding measurement-period adjustments.

Schedule of Significant Items Included in Other Income (Deductions)

The following table provides the composition of significant items included in Other income (deductions) in Southwest’s and the Company’s Condensed Consolidated Statements of Income:


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Southwest Gas Corporation:
Change in COLI policies	$	(5,200)	$	3,100	$	(7,200)	$	5,800	$	(4,200)	$	18,500
Interest income	3,198		1,231		5,999		1,947		9,165		4,160
Equity AFUDC	81		(981)		157		—		157		2,543
Other components of net periodic benefit cost	(187)		(3,505)		(375)		(7,010)		(7,386)		(17,021)
Miscellaneous income and (expense)	(1,325)		(1,010)		(699)		(1,352)		(3,798)		(2,689)
Southwest Gas Corporation - total other income (deductions)	(3,433)		(1,165)		(2,118)		(615)		(6,062)		5,493
Centuri, MountainWest, and Southwest Gas Holdings, Inc.:

Foreign transaction gain (loss)	214		(9)		217		(12)		207		(12)
Equity AFUDC	236		—		418		—		418		—
Equity in earnings of unconsolidated investments	728		109		1,243		101		1,368		156
Miscellaneous income and (expense)	(580)		(246)		(1,351)		(337)		(158)		(444)
Southwest Gas Holdings, Inc. - total other income (deductions)	$	(2,835)	$	(1,311)	$	(1,591)	$	(863)	$	(4,227)	$	5,193

Summary of Redeemable Noncontrolling Interest

The following depicts changes to the balances of the redeemable noncontrolling interests:


(Thousands of dollars):	Linetec		Drum		Total
Balance, December 31, 2021	$	184,148	$	12,569	$	196,717
Net income (loss) attributable to redeemable noncontrolling interests	1,576		(10)		1,566
Redemption value adjustments	(35,978)		—		(35,978)
Redemption of equity interest from noncontrolling party	(39,649)		—		(39,649)
Balance, June 30, 2022	$	110,097	$	12,559	$	122,656

Schedule of Earnings Per Share, Basic and Diluted

A reconciliation of the denominator used in Basic and Diluted EPS calculations is shown in the following table:


	Three Months Ended June 30,		Six Months Ended June 30,		Twelve Months Ended June 30,
(In thousands)	2022	2021	2022	2021	2022	2021
Weighted average basic shares	67,045	58,607	63,909	58,106	62,022	57,348
Effect of dilutive securities:
Restricted stock units (1)	145	103	132	91	135	92
Weighted average diluted shares	67,190	58,710	64,041	58,197	62,157	57,440

- Definition

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
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-Paragraph 1
-Subparagraph (c)
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

+ Details

Components of Net Periodic Benefit Cost (Tables)

6 Months Ended

Jun. 30, 2022

Retirement Benefits [Abstract]

Schedule of Net Periodic Benefit Costs


	Qualified Retirement Plan
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	11,028	$	10,290	$	22,056	$	20,580	$	42,635	$	37,730
Interest cost	11,251		10,108		22,502		20,216		42,718		42,994
Expected return on plan assets	(19,978)		(18,088)		(39,956)		(36,176)		(76,132)		(68,824)
Amortization of net actuarial loss	8,117		10,489		16,234		20,978		37,211		38,990
Net periodic benefit cost	$	10,418	$	12,799	$	20,836	$	25,598	$	46,432	$	50,890

	SERP
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	106	$	132	$	212	$	263	$	475	$	457
Interest cost	360		358		720		716		1,435		1,517
Amortization of net actuarial loss	587		660		1,175		1,320		2,497		2,223
Net periodic benefit cost	$	1,053	$	1,150	$	2,107	$	2,299	$	4,407	$	4,197

	PBOP
	June 30,
	Three Months				Six Months				Twelve Months
	2022		2021		2022		2021		2022		2021
(Thousands of dollars)
Service cost	$	485	$	423	$	970	$	846	$	1,815	$	1,636
Interest cost	613		548		1,226		1,096		2,323		2,388
Expected return on plan assets	(807)		(810)		(1,614)		(1,620)		(3,233)		(3,324)
Amortization of prior service costs	44		240		88		480		567		1,057

Net periodic benefit cost	$	335	$	401	$	670	$	802	$	1,472	$	1,757

Revenue (Tables)

6 Months Ended

Jun. 30, 2022

Revenue from Contract with Customer [Abstract]

Summary of Revenue Disaggregated by Service Type and Contract Type


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Residential	$	228,573	$	193,322	$	743,159	$	596,465	$	1,182,306	$	995,132
Small commercial	78,730		56,093		202,714		137,491		335,437		235,114
Large commercial	20,989		13,158		41,150		25,831		72,690		47,818
Industrial/other	10,773		6,974		20,745		20,744		42,314		33,785
Transportation	24,466		21,797		51,098		46,333		97,005		90,307
Revenue from contracts with customers	363,531		291,344		1,058,866		826,864		1,729,752		1,402,156
Alternative revenue program revenues (deferrals)	11,022		(1,531)		(12,477)		(17,904)		18,608		(6,110)
Other revenues (1)	3,389		2,983		8,092		5,768		13,183		4,006
Total Regulated operations revenues	$	377,942	$	292,796	$	1,054,481	$	814,728	$	1,761,543	$	1,400,052


	Three Months Ended June 30,				Six Months Ended June 30,				Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022		2021		2022		2021
Service Types:
Gas infrastructure services	$	418,869	$	346,877	$	679,551	$	568,714	$	1,413,177	$	1,282,008
Electric power infrastructure services	179,749		97,644		361,717		191,605		695,314		435,825
Other	107,472		84,104		188,699		132,281		387,537		294,749
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967	$	892,600	$	2,496,028	$	2,012,582


	Three Months Ended June 30,				Six Months Ended June 30,					Twelve Months Ended June 30,
(Thousands of dollars)	2022		2021		2022			2021		2022			2021
Contract Types:
Master services agreement	$	617,489	$	398,650	$	1,062,834	*	$	692,330	$	2,023,482	*	$	1,543,292
Bid contract	88,601		129,975		167,133		*	200,270		472,546		*	469,290
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967		$	892,600	$	2,496,028		$	2,012,582

Unit price contracts	$	421,927	$	361,926	$	724,450		$	596,375	$	1,497,157		$	1,344,626
Fixed price contracts	128,793		50,455		215,330			85,049		398,023			179,194
Time and materials contracts	155,370		116,244		290,187			211,176		600,848			488,762
Total Utility infrastructure services revenues	$	706,090	$	528,625	$	1,229,967		$	892,600	$	2,496,028		$	2,012,582


	Three Months Ended June 30,		Six Months Ended June 30,
(Thousands of dollars)	2022
Regulated gas transportation and storage revenues	$	57,786	119,763
NGL revenues	1,876		3,369
Other revenues	2,380		5,859
Revenue from contracts with customers	62,042		128,991
Other revenues	46		90
Total Regulated operations revenues	$	62,088	129,081

Summary of Information about Receivables, Revenue Earned on Contracts in Progress in Excess of Billings, Which are Included Within Accounts Receivable, Net of Allowances, and Amounts Billed in Excess of Revenue Earned on Contracts


(Thousands of dollars)	June 30, 2022		December 31, 2021
Contracts receivable, net	$	332,433	$	296,005
Revenue earned on contracts in progress in excess of billings	254,259		214,774
Amounts billed in excess of revenue earned on contracts	13,738		11,860

Schedule of Utility Infrastructure Services Contracts Receivable

Utility infrastructure services contracts receivable consists of the following:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Billed on completed contracts and contracts in progress	$	331,173	$	292,770
Other receivables	1,408		3,492
Contracts receivable, gross	332,581		296,262
Allowance for doubtful accounts	(148)		(257)
Contracts receivable, net	$	332,433	$	296,005

Common Stock (Tables)

6 Months Ended

Jun. 30, 2022

Equity [Abstract]

Schedule of Common Stock Activity

The following table provides the life-to-date activity under that program through June 30, 2022:




Gross proceeds	$	158,180,343
Less: agent commissions	(1,581,803)
Net proceeds	$	156,598,540
Number of shares sold	2,302,407
Weighted average price per share	$	68.70

Debt (Tables)

6 Months Ended

Jun. 30, 2022

Debt Disclosure [Abstract]

Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt

Details surrounding the fair value and individual carrying values of instruments are provided in the table that follows.


	June 30, 2022				December 31, 2021
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
(Thousands of dollars)
Southwest Gas Corporation:
Debentures:
Notes, 6.1%, due 2041	$	125,000	$	126,410	$	125,000	$	166,380
Notes, 4.05%, due 2032	600,000		549,396		—		—
Notes, 3.875%, due 2022	—		—		250,000		250,603
Notes, 4.875%, due 2043	250,000		230,653		250,000		307,538
Notes, 3.8%, due 2046	300,000		235,140		300,000		329,055
Notes, 3.7%, due 2028	300,000		283,260		300,000		325,191
Notes, 4.15%, due 2049	300,000		250,461		300,000		342,030
Notes, 2.2%, due 2030	450,000		365,054		450,000		440,838
Notes, 3.18%, due 2051	300,000		211,326		300,000		292,116
8% Series, due 2026	75,000		84,078		75,000		92,623
Medium-term notes, 7.78% series, due 2022	—		—		25,000		25,122
Medium-term notes, 7.92% series, due 2027	25,000		27,821		25,000		31,555
Medium-term notes, 6.76% series, due 2027	7,500		7,839		7,500		8,949
Unamortized discount and debt issuance costs	(26,627)				(19,959)
	2,705,873				2,387,541
Revolving credit facility and commercial paper	—		—		130,000		130,000
Industrial development revenue bonds:
Tax-exempt Series A, due 2028	50,000		50,000		50,000		50,000
2003 Series A, due 2038	50,000		50,000		50,000		50,000
2008 Series A, due 2038	50,000		50,000		50,000		50,000
2009 Series A, due 2039	50,000		50,000		50,000		50,000
Unamortized discount and debt issuance costs	(1,774)				(1,938)
	198,226				198,062
Less: current maturities	—				(275,000)
Southwest Gas Corporation total long-term debt, less current maturities	$	2,904,099			$	2,440,603
Southwest Gas Holdings, Inc.:
Centuri secured term loan facility	$	1,011,413	$	970,329	$	1,117,138	$	1,117,841
Centuri secured revolving credit facility	145,885		145,759		103,329		103,749
MountainWest unsecured senior notes, 3.53%, due in 2028	101,922		90,430		102,078		102,078
MountainWest unsecured senior notes, 4.875%, due in 2041	199,599		157,894		199,926		199,926
MountainWest unsecured senior notes, 3.91%, due in 2038	147,786		113,703		147,735		147,735
Other debt obligations	141,653		129,810		51,665		50,003
Unamortized discount and debt issuance costs	(22,627)				(24,466)
Less: current maturities	(41,276)				(22,324)
Southwest Gas Holdings, Inc. total long-term debt, less current maturities	$	4,588,454			$	4,115,684

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Paragraph 1
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Other Comprehensive Income and Accumulated Other Comprehensive Income (Tables)

6 Months Ended

Jun. 30, 2022

Equity [Abstract]

Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss)


	Three Months Ended June 30, 2022						Three Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Amortization of prior service cost	$	44	$	(11)	$	33	$	240	$	(58)	$	182
Amortization of net actuarial (gain)/loss	8,704		(2,089)		6,615		11,148		(2,676)		8,472
Regulatory adjustment	(7,268)		1,744		(5,524)		(9,575)		2,298		(7,277)
Pension plans other comprehensive income (loss)	1,480		(356)		1,124		1,813		(436)		1,377
FSIRS (designated hedging activities):
Amounts reclassified into net income	—		—		—		544		(130)		414
FSIRS other comprehensive income (loss)	—		—		—		544		(130)		414
Total other comprehensive income (loss) - Southwest Gas Corporation	1,480		(356)		1,124		2,357		(566)		1,791
Foreign currency translation adjustments:
Translation adjustments	(2,680)		—		(2,680)		909		—		909
Foreign currency other comprehensive income (loss)	(2,680)		—		(2,680)		909		—		909
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	(1,200)	$	(356)	$	(1,556)	$	3,266	$	(566)	$	2,700

	Six Months Ended June 30, 2022						Six Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Amortization of prior service cost	$	88	$	(22)	$	66	$	480	$	(116)	$	364
Amortization of net actuarial (gain)/loss	17,409		(4,178)		13,231		22,297		(5,351)		16,946
Regulatory adjustment	(14,536)		3,489		(11,047)		(19,150)		4,596		(14,554)
Pension plans other comprehensive income (loss)	2,961		(711)		2,250		3,627		(871)		2,756
FSIRS (designated hedging activities):
Amounts reclassified into net income	545		(129)		416		1,088		(261)		827
FSIRS other comprehensive income (loss)	545		(129)		416		1,088		(261)		827
Total other comprehensive income (loss) - Southwest Gas Corporation	3,506		(840)		2,666		4,715		(1,132)		3,583
Foreign currency translation adjustments:
Translation adjustments	(1,433)		—		(1,433)		1,732		—		1,732
Foreign currency other comprehensive income (loss)	(1,433)		—		(1,433)		1,732		—		1,732
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	2,073	$	(840)	$	1,233	$	6,447	$	(1,132)	$	5,315


	Twelve Months Ended June 30, 2022						Twelve Months Ended June 30, 2021
(Thousands of dollars)	Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount		Before- Tax Amount		Tax (Expense) or Benefit (1)		Net-of- Tax Amount
Defined benefit pension plans:
Net actuarial gain/(loss)	$	59,176	$	(14,202)	$	44,974	$	(57,539)	$	13,809	$	(43,730)
Amortization of prior service cost	567		(136)		431		1,057		(255)		802
Amortization of net actuarial (gain)/loss	39,709		(9,530)		30,179		41,212		(9,890)		31,322

Regulatory adjustment	(83,580)		20,060		(63,520)		5,075		(1,219)		3,856
Pension plans other comprehensive income (loss)	15,872		(3,808)		12,064		(10,195)		2,445		(7,750)
FSIRS (designated hedging activities):
Amounts reclassified into net income	1,631		(390)		1,241		2,662		(639)		2,023
FSIRS other comprehensive income (loss)	1,631		(390)		1,241		2,662		(639)		2,023
Total other comprehensive income (loss) - Southwest Gas Corporation	17,503		(4,198)		13,305		(7,533)		1,806		(5,727)
Foreign currency translation adjustments:
Translation adjustments	(3,145)		—		(3,145)		5,656		—		5,656
Foreign currency other comprehensive income (loss)	(3,145)		—		(3,145)		5,656		—		5,656
Total other comprehensive income (loss) - Southwest Gas Holdings, Inc.	$	14,358	$	(4,198)	$	10,160	$	(1,877)	$	1,806	$	(71)

Schedule of Rollforward of Accumulated Other Comprehensive Income

The following table represents a rollforward of AOCI, presented on the Company’s Condensed Consolidated Balance Sheets and its Condensed Consolidated Statements of Equity:


	Defined Benefit Plans						FSIRS						Foreign Currency Items
(Thousands of dollars)	Before-Tax		Tax (Expense) Benefit (4)		After-Tax		Before-Tax		Tax (Expense) Benefit (4)		After-Tax		Before-Tax		Tax (Expense) Benefit		After-Tax		AOCI
Beginning Balance AOCI December 31, 2021	$	(61,182)	$	14,685	$	(46,497)	$	(545)	$	129	$	(416)	$	152	$	—	$	152	$	(46,761)
Translation adjustments	—		—		—		—		—		—		(1,433)		—		(1,433)		(1,433)
Other comprehensive income (loss) before reclassifications	—		—		—		—		—		—		(1,433)		—		(1,433)		(1,433)
FSIRS amount reclassified from AOCI (1)	—		—		—		545		(129)		416		—		—		—		416
Amortization of prior service cost (2)	88		(22)		66		—		—		—		—		—		—		66
Amortization of net actuarial loss (2)	17,409		(4,178)		13,231		—		—		—		—		—		—		13,231
Regulatory adjustment (3)	(14,536)		3,489		(11,047)		—		—		—		—		—		—		(11,047)
Net current period other comprehensive income (loss) attributable to Southwest Gas Holdings, Inc.	2,961		(711)		2,250		545		(129)		416		(1,433)		—		(1,433)		1,233
Ending Balance AOCI June 30, 2022	$	(58,221)	$	13,974	$	(44,247)	$	—	$	—	$	—	$	(1,281)	$	—	$	(1,281)	$	(45,528)

(1)The FSIRS reclassification amount is included in Net interest deductions on the Company’s Condensed Consolidated Statements of Income.

(2)These AOCI components are included in the computation of net periodic benefit cost (see Note 2 – Components of Net Periodic Benefit Cost for additional details).

(4)Tax amounts are calculated using a 24% rate.

The following table represents a rollforward of AOCI, presented on Southwest’s Condensed Consolidated Balance Sheets:


	Defined Benefit Plans						FSIRS
(Thousands of dollars)	Before-Tax		Tax (Expense) Benefit (8)		After-Tax		Before-Tax		Tax (Expense) Benefit (8)		After-Tax		AOCI
Beginning Balance AOCI December 31, 2021	$	(61,182)	$	14,685	$	(46,497)	$	(545)	$	129	$	(416)	$	(46,913)
FSIRS amount reclassified from AOCI (5)	—		—		—		545		(129)		416		416
Amortization of prior service cost (6)	88		(22)		66		—		—		—		66
Amortization of net actuarial loss (6)	17,409		(4,178)		13,231		—		—		—		13,231
Regulatory adjustment (7)	(14,536)		3,489		(11,047)		—		—		—		(11,047)
Net current period other comprehensive income attributable to Southwest Gas Corporation	2,961		(711)		2,250		545		(129)		416		2,666
Ending Balance AOCI June 30, 2022	$	(58,221)	$	13,974	$	(44,247)	$	—	$	—	$	—	$	(44,247)

(5) The FSIRS reclassification amount is included in Net interest deductions on Southwest’s Condensed Consolidated Statements of Income.

(6)These AOCI components are included in the computation of net periodic benefit cost (see Note 2 – Components of Net Periodic Benefit Cost for additional details).

(8)Tax amounts are calculated using a 24% rate.

The following table represents amounts (before income tax impacts) included in AOCI (in the tables above), that have not yet been recognized in net periodic benefit cost:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Net actuarial loss	$	(381,601)	$	(399,010)
Prior service cost	(1,440)		(1,528)
Less: amount recognized in regulatory assets	324,820		339,356
Recognized in AOCI	$	(58,221)	$	(61,182)

Schedule of Amount Recognized Before Income Tax in Accumulated Other Comprehensive Income

The following table represents amounts (before income tax impacts) included in AOCI (in the tables above), that have not yet been recognized in net periodic benefit cost:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Net actuarial loss	$	(381,601)	$	(399,010)
Prior service cost	(1,440)		(1,528)
Less: amount recognized in regulatory assets	324,820		339,356
Recognized in AOCI	$	(58,221)	$	(61,182)

Segment Information (Tables)

6 Months Ended

Jun. 30, 2022

Segment Reporting [Abstract]

Schedule Of Accounts Receivable Not Eliminated During Consolidation

Accounts receivable for these services, which are not eliminated during consolidation, are presented in the table below:


(Thousands of dollars)	June 30, 2022		December 31, 2021
Centuri accounts receivable for services provided to Southwest	$	16,915	$	15,166

Schedule of Segment Reporting Information

The financial information pertaining to the natural gas distribution, utility infrastructure services, and pipeline and storage segments are as follows:


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Three Months Ended June 30, 2022
Revenues from external customers	$	377,942	$	672,119	$	62,088	$	—	$	1,112,149
Intersegment revenues	—		33,971		—		—		33,971
Total	$	377,942	$	706,090	$	62,088	$	—	$	1,146,120
Segment net income (loss)	$	(2,266)	$	4,741	$	15,076	$	(24,126)	$	(6,575)

Three Months Ended June 30, 2021
Revenues from external customers	$	292,796	$	504,941	$	—	$	—	$	797,737
Intersegment revenues	—		23,684		—		—		23,684
Total	$	292,796	$	528,625	$	—	$	—	$	821,421
Segment net income (loss)	$	11,413	$	15,116	$	—	$	(1,410)	$	25,119

(Thousands of dollars)	Natural Gas Operations		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Six Months Ended June 30, 2022
Revenues from external customers	$	1,054,481	$	1,167,663	$	129,081	$	—	$	2,351,225
Intersegment revenues	—		62,304		—		—		62,304
Total	$	1,054,481	$	1,229,967	$	129,081	$	—	$	2,413,529
Segment net income (loss)	$	109,529	$	(18,745)	$	32,006	$	(33,187)	$	89,603

Six Months Ended June 30, 2021
Revenues from external customers	$	814,728	$	844,713	$	—	$	—	$	1,659,441
Intersegment revenues	—		47,887		—		—		47,887
Total	$	814,728	$	892,600	$	—	$	—	$	1,707,328
Segment net income (loss)	$	130,128	$	14,257	$	—	$	(1,973)	$	142,412


(Thousands of dollars)	Natural Gas Distribution		Utility Infrastructure Services		Pipeline and Storage		Other		Total
Twelve Months Ended June 30, 2022
Revenues from external customers	$	1,761,543	$	2,379,265	$	129,081	$	—	$	4,269,889
Intersegment revenues	—		116,763		—		—		116,763
Total	$	1,761,543	$	2,496,028	$	129,081	$	—	$	4,386,652
Segment net income (loss)	$	166,536	$	7,418	$	32,006	$	(57,990)	$	147,970

Twelve Months Ended June 30, 2021
Revenues from external customers	$	1,400,052	$	1,899,961	$	—	$	—	$	3,300,013
Intersegment revenues	—		112,621		—		—		112,621
Total	$	1,400,052	$	2,012,582	$	—	$	—	$	3,412,634
Segment net income (loss)	$	193,705	$	73,056	$	—	$	(2,532)	$	264,229

Business Acquisitions (Tables)

6 Months Ended

Jun. 30, 2022

Business Combination and Asset Acquisition [Abstract]

Summary of Fair Values of Assets Acquired and Liabilities Assumed

The preliminary estimated fair values of assets acquired and liabilities assumed as of August 27, 2021, and as updated through June 30, 2022, are as follows:


(Millions of dollars)	Acquisition Date		Measurement Period Adjustments		Revised Acquisition Date
Cash and cash equivalents	$	1.9	$	—	$	1.9
Accounts receivable	69.1		(8.6)		60.5
Contract assets	40.1		7.4		47.5
Income taxes receivable, net	0.7		—		0.7
Right of use assets under operating leases	1.5		—		1.5
Prepaid expenses	5.2		—		5.2
Property and equipment	118.1		1.2		119.3
Intangible assets	335.0		(31.5)		303.5
Goodwill	446.8		1.8		448.6
Total assets acquired	1,018.4		$	(29.7)	$	988.7

Trade and other payables	46.2		—		46.2
Finance lease obligations	27.5		1.2		28.7
Contract liabilities	12.7		—		12.7
Operating lease obligations	1.5		—		1.5
Other liabilities	5.3		(1.2)		4.1
Deferred tax liabilities	94.8		(23.4)		71.4
Total liabilities assumed and noncontrolling interest	188.0		(23.4)		164.6
Net assets acquired	$	830.4	$	(6.3)	$	824.1

The preliminary estimated fair values of assets acquired and liabilities assumed as of December 31, 2021, and as updated through June 30, 2022, are as follows:


(Millions of dollars)	Acquisition Date		Measurement Period Adjustments		Revised Acquisition Date
Gas plant, net	$	1,047.4	$	—	$	1,047.4
Other property and investments	51.3		—		51.3
Cash and cash equivalents	17.6		—		17.6
Accounts receivable, net of allowances	26.6		2.9		29.5
Prepaid and other current assets	27.4		—		27.4
Deferred charges and other assets	31.1		—		31.1
Goodwill	986.2		(28.2)		958.0
Deferred income taxes, net	15.4		20.9		36.3
Total assets acquired	2,203.0		(4.4)		2,198.6

Long-term debt	449.7		—		449.7
Accounts payable	7.0		—		7.0
Deferred purchased gas costs	5.7		—		5.7
Customer deposits	3.2		—		3.2
Accrued general taxes	0.4		—		0.4
Accrued interest	4.7		—		4.7
Other current liabilities	14.5		—		14.5
Accumulated removal costs	56.6		—		56.6
Other deferred credits	85.6		—		85.6
Total liabilities assumed	627.4		—		627.4
Net assets acquired	$	1,575.6	$	(4.4)	$	1,571.2

Background, Organization, and Summary of Significant Accounting Policies - Narratives (Details)	1 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2022 USD ($)	Aug. 31, 2021 person	Jun. 30, 2022 USD ($) director	Jun. 30, 2022 USD ($) director	Jun. 30, 2022 USD ($) director	May 09, 2022 $ / shares	Dec. 31, 2021 USD ($)	Nov. 30, 2021	Oct. 10, 2021	Nov. 30, 2018
Significant Accounting Policies [Line Items]
Number of new board of directors appointed \| director			3	3	3
Rights agreement amendment, beneficial ownership percentage						24.90%			10.00%
Rights agreement amendment, updated tender price (in USD per share) \| $ / shares						$ 82.50
Capital expenditures incurred but not yet paid, increase (decrease)				$ (11,600,000)	$ 6,500,000
Deferred purchased gas costs recovered or refunded period				1 year
Gas pipe materials and operating supplies			$ 74,500,000	$ 74,500,000	74,500,000		$ 67,400,000
Accrued purchased gas cost			10,200,000	10,200,000	10,200,000		52,000,000
Goodwill impairment				0
Dividends declared but not yet paid			41,500,000	41,500,000	41,500,000		36,000,000
Payments for redemption of redeemable noncontrolling interest	$ 39,600,000
Percentage of redeemable noncontrolling interest redeemed	5.00%
Redemption value adjustments				35,978,000
Loss contingency, number of individuals injured \| person		4
Linetec
Significant Accounting Policies [Line Items]
Redemption value adjustments				35,978,000
Drum
Significant Accounting Policies [Line Items]
Redemption value adjustments				0
Money Market Funds
Significant Accounting Policies [Line Items]
Money market fund investments			97,000,000	97,000,000	97,000,000		20,000,000
Southwest Gas Corporation
Significant Accounting Policies [Line Items]
Capital expenditures incurred but not yet paid, increase (decrease)				(18,300,000)	6,600,000
Gas pipe materials and operating supplies			70,200,000	70,200,000	70,200,000		62,900,000
Self-insured retention amount			1,000,000	1,000,000	1,000,000
Threshold amount above self-insured retention			4,000,000	4,000,000	4,000,000
Loss contingency, maximum			5,000,000	5,000,000	5,000,000
Loss contingency accrual							5,000,000
Loss contingency recorded			6,200,000
Southwest Gas Corporation \| Money Market Funds
Significant Accounting Policies [Line Items]
Money market fund investments			$ 77,000,000	$ 77,000,000	$ 77,000,000		$ 0
Previous Owner Of Linetec \| Linetec
Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners	15.00%									20.00%
Certain Members Of Riggs Distler Management \| Drum
Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners			1.42%	1.42%	1.42%			1.42%
Minimum
Significant Accounting Policies [Line Items]
Number of new board of directors appointed \| director			2	2	2
Number of strategic transactions committee directors \| director			3	3	3
Minimum \| Centuri
Significant Accounting Policies [Line Items]
Entity separation, completion period	9 months
Maximum
Significant Accounting Policies [Line Items]
Number of strategic transactions committee directors \| director			6	6	6
Maximum \| Centuri
Significant Accounting Policies [Line Items]
Entity separation, completion period	12 months

Background, Organization, and Summary of Significant Accounting Policies - Schedule of Other Property and Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Other property and investments	$ 57,049	$ 59,337
Total	1,312,701	1,316,479
Non-regulated property, equipment, and intangibles	1,678,683	1,616,392
Non-regulated accumulated provision for depreciation and amortization	(569,630)	(512,343)
Southwest Gas Corporation
Property, Plant and Equipment [Line Items]
Net cash surrender value of COLI policies	142,819	149,947
Other property and investments	3,780	3,146
Total	$ 146,599	$ 153,093

Background, Organization, and Summary of Significant Accounting Policies - Schedule of Goodwill (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 1,781,332
Foreign currency translation adjustment	(1,776)
Goodwill, ending balance	1,750,472
Riggs Distler
Goodwill [Roll Forward]
Measurement period adjustments	(906)
MountainWest
Goodwill [Roll Forward]
Measurement period adjustments	(28,178)
Natural Gas Distribution
Goodwill [Roll Forward]
Goodwill, beginning balance	10,095
Foreign currency translation adjustment	0
Goodwill, ending balance	10,095
Natural Gas Distribution \| Riggs Distler
Goodwill [Roll Forward]
Measurement period adjustments	0
Natural Gas Distribution \| MountainWest
Goodwill [Roll Forward]
Measurement period adjustments	0
Utility Infrastructure Services
Goodwill [Roll Forward]
Goodwill, beginning balance	785,058
Foreign currency translation adjustment	(1,776)
Goodwill, ending balance	782,376
Utility Infrastructure Services \| Riggs Distler
Goodwill [Roll Forward]
Measurement period adjustments	(906)
Utility Infrastructure Services \| MountainWest
Goodwill [Roll Forward]
Measurement period adjustments	0
Pipeline and Storage
Goodwill [Roll Forward]
Goodwill, beginning balance	986,179
Foreign currency translation adjustment	0
Goodwill, ending balance	958,001
Pipeline and Storage \| Riggs Distler
Goodwill [Roll Forward]
Measurement period adjustments
Pipeline and Storage \| MountainWest
Goodwill [Roll Forward]
Measurement period adjustments	$ (28,178)

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

Background, Organization, and Summary of Significant Accounting Policies - Other Income (Deductions) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Other income (deductions)
Equity AFUDC	$ 236	$ 0	$ 418	$ 0	$ 418	$ 0
Miscellaneous income and (expense)	(580)	(246)	(1,351)	(337)	(158)	(444)
Foreign transaction gain (loss)	214	(9)	217	(12)	207	(12)
Equity in earnings of unconsolidated investments	728	109	1,243	101	1,368	156
Total other income (deductions)	(2,835)	(1,311)	(1,591)	(863)	(4,227)	5,193
Southwest Gas Corporation
Other income (deductions)
Change in COLI policies	(5,200)	3,100	(7,200)	5,800	(4,200)	18,500
Interest income	3,198	1,231	5,999	1,947	9,165	4,160
Equity AFUDC	81	(981)	157	0	157	2,543
Other components of net periodic benefit cost	(187)	(3,505)	(375)	(7,010)	(7,386)	(17,021)
Miscellaneous income and (expense)	(1,325)	(1,010)	(699)	(1,352)	(3,798)	(2,689)
Total other income (deductions)	$ (3,433)	$ (1,165)	$ (2,118)	$ (615)	$ (6,062)	$ 5,493

Background, Organization, and Summary of Significant Accounting Policies - Summary of Redeemable Noncontrolling Interest (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Movement In Redeemable Noncontrolling Interest [Roll Forward]
Redeemable noncontrolling interest, beginning balance	$ 196,717
Net income (loss) attributable to redeemable noncontrolling interests	1,566
Redemption value adjustments	(35,978)
Redemption of equity interest from noncontrolling party	(39,649)
Redeemable noncontrolling interest, ending balance	122,656
Linetec
Movement In Redeemable Noncontrolling Interest [Roll Forward]
Redeemable noncontrolling interest, beginning balance	184,148
Net income (loss) attributable to redeemable noncontrolling interests	1,576
Redemption value adjustments	(35,978)
Redemption of equity interest from noncontrolling party	(39,649)
Redeemable noncontrolling interest, ending balance	110,097
Drum
Movement In Redeemable Noncontrolling Interest [Roll Forward]
Redeemable noncontrolling interest, beginning balance	12,569
Net income (loss) attributable to redeemable noncontrolling interests	(10)
Redemption value adjustments	0
Redemption of equity interest from noncontrolling party	0
Redeemable noncontrolling interest, ending balance	$ 12,559

Background, Organization, and Summary of Significant Accounting Policies - Schedule of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Weighted average basic shares (in shares)	67,045	58,607	63,909	58,106	62,022	57,348
Effect of dilutive securities:
Restricted stock units (in shares)	145	103	132	91	135	92
Weighted average diluted shares (in shares)	67,190	58,710	64,041	58,197	62,157	57,440
Number of performance share units granted (in shares)	136	95	125	85	124	83

Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Qualified Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11,028	$ 10,290	$ 22,056	$ 20,580	$ 42,635	$ 37,730
Interest cost	11,251	10,108	22,502	20,216	42,718	42,994
Expected return on plan assets	(19,978)	(18,088)	(39,956)	(36,176)	(76,132)	(68,824)
Amortization of net actuarial loss	8,117	10,489	16,234	20,978	37,211	38,990
Net periodic benefit cost	10,418	12,799	20,836	25,598	46,432	50,890
SERP
Defined Benefit Plan Disclosure [Line Items]
Service cost	106	132	212	263	475	457
Interest cost	360	358	720	716	1,435	1,517
Amortization of net actuarial loss	587	660	1,175	1,320	2,497	2,223
Net periodic benefit cost	1,053	1,150	2,107	2,299	4,407	4,197
PBOP
Defined Benefit Plan Disclosure [Line Items]
Service cost	485	423	970	846	1,815	1,636
Interest cost	613	548	1,226	1,096	2,323	2,388
Expected return on plan assets	(807)	(810)	(1,614)	(1,620)	(3,233)	(3,324)
Amortization of prior service costs	44	240	88	480	567	1,057
Net periodic benefit cost	$ 335	$ 401	$ 670	$ 802	$ 1,472	$ 1,757

Revenue - Schedule of Regulated Operations Revenues: Natural Gas Distribution Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total Regulated operations revenues	$ 440,030	$ 292,796	$ 1,183,562	$ 814,728	$ 1,890,624	$ 1,400,052
Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	363,531	291,344	1,058,866	826,864	1,729,752	1,402,156
Alternative revenue program revenues (deferrals)	11,022	(1,531)	(12,477)	(17,904)	18,608	(6,110)
Other revenues	3,389	2,983	8,092	5,768	13,183	4,006
Total Regulated operations revenues	377,942	292,796	1,054,481	814,728	1,761,543	1,400,052
Residential \| Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	228,573	193,322	743,159	596,465	1,182,306	995,132
Small commercial \| Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	78,730	56,093	202,714	137,491	335,437	235,114
Large commercial \| Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20,989	13,158	41,150	25,831	72,690	47,818
Industrial/other \| Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,773	6,974	20,745	20,744	42,314	33,785
Transportation \| Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 24,466	$ 21,797	$ 51,098	$ 46,333	$ 97,005	$ 90,307

Revenue - Schedule of Regulated Operations Revenues: Utility Infrastructure Services Segment (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 706,090		$ 528,625	$ 1,229,967	$ 892,600	$ 2,496,028	$ 2,012,582
Master services agreement \| Understatement Of Master Services Category
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		$ (88,800)
Master services agreement \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	617,489		398,650	1,062,834	692,330	2,023,482	1,543,292
Bid contract \| Overstatement Of Bid Contract Category
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		$ 88,800
Bid contract \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	88,601		129,975	167,133	200,270	472,546	469,290
Unit price contracts \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	421,927		361,926	724,450	596,375	1,497,157	1,344,626
Fixed price contracts \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	128,793		50,455	215,330	85,049	398,023	179,194
Time and materials contracts \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	155,370		116,244	290,187	211,176	600,848	488,762
Gas infrastructure services \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	418,869		346,877	679,551	568,714	1,413,177	1,282,008
Electric power infrastructure services \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	179,749		97,644	361,717	191,605	695,314	435,825
Other \| Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 107,472		$ 84,104	$ 188,699	$ 132,281	$ 387,537	$ 294,749

Revenue - Summary of Information about Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Contracts receivable, net	$ 332,433	$ 296,005
Revenue earned on contracts in progress in excess of billings	254,259	214,774
Amounts billed in excess of revenue earned on contracts	$ 13,738	$ 11,860

Revenue - Narratives (Details) $ in Millions	6 Months Ended
Revenue - Narratives (Details) $ in Millions	Jun. 30, 2022 USD ($) contract
Segment Reporting Information [Line Items]
Change in contract liability, revenue recognized	$ 11.9
Centuri
Segment Reporting Information [Line Items]
Number of contracts with original duration more than one year \| contract	47
Centuri \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-07-01
Segment Reporting Information [Line Items]
Transaction price allocated to unsatisfied performance obligations of contracts	$ 465.7
Transaction price allocated to unsatisfied performance obligations of contracts, period	2 years 10 months 24 days

Revenue - Schedule of Utility Infrastructure Services Contracts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Contracts receivable, net	$ 332,433	$ 296,005
Utility Infrastructure Services
Disaggregation of Revenue [Line Items]
Contracts receivable, gross	332,581	296,262
Allowance for doubtful accounts	(148)	(257)
Contracts receivable, net	332,433	296,005
Utility Infrastructure Services \| Billed on completed contracts and contracts in progress
Disaggregation of Revenue [Line Items]
Contracts receivable, gross	331,173	292,770
Utility Infrastructure Services \| Other receivables
Disaggregation of Revenue [Line Items]
Contracts receivable, gross	$ 1,408	$ 3,492

Revenue - Schedule of Regulated Operations Revenues: Pipeline and Storage Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Total Regulated operations revenues	$ 440,030	$ 292,796	$ 1,183,562	$ 814,728	$ 1,890,624	$ 1,400,052
Pipeline and Storage
Segment Reporting Information [Line Items]
Revenue from contracts with customers	62,042		128,991
Other revenues	46		90
Total Regulated operations revenues	62,088		129,081
Pipeline and Storage \| Regulated gas transportation and storage revenues
Segment Reporting Information [Line Items]
Revenue from contracts with customers	57,786		119,763
Pipeline and Storage \| NGL revenues
Segment Reporting Information [Line Items]
Revenue from contracts with customers	1,876		3,369
Pipeline and Storage \| Other revenues
Segment Reporting Information [Line Items]
Revenue from contracts with customers	$ 2,380		$ 5,859

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Common Stock - Narratives (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended		6 Months Ended
	Mar. 31, 2022	Nov. 30, 2021	Jun. 30, 2022	May 09, 2022	Oct. 10, 2021	Apr. 08, 2021
Class of Stock [Line Items]
Sale of stock, number of shares	6,325
Sale of stock, price per share (in USD per share)			$ 74.00
Net proceeds from sale of stock	$ 452,300,000
Sale of stock, underwriters' discount	$ 15,800,000
Rights agreement amendment, beneficial ownership percentage				24.90%	10.00%
Term Loan Facility Due December 30, 2022 \| Loans Payable
Class of Stock [Line Items]
Debt instrument, term		364 days
Restricted Stock/Unit Plan, and Management Incentive Plan
Class of Stock [Line Items]
Common stock issued (in shares)			191
Dividend Reinvestment and Stock Purchase Plan
Class of Stock [Line Items]
Common stock issued (in shares)			66
Common stock issued, amount			$ 5,100,000
Equity Shelf Program
Class of Stock [Line Items]
Sale of stock, amount of common stock offered for sale						$ 500,000,000
Sale of stock, amount of common stock available for sale			$ 341,800,000

Common Stock - Activity of Equity Shelf Program (Details) - USD ($)	6 Months Ended		12 Months Ended		15 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022
Class of Stock [Line Items]
Net proceeds	$ 456,280,000	$ 121,302,000	$ 548,619,000	$ 205,049,000
Equity Shelf Program
Class of Stock [Line Items]
Gross proceeds					$ 158,180,343
Less: agent commissions					(1,581,803)
Net proceeds					$ 156,598,540
Number of shares sold (in shares)					2,302,407
Weighted average price per share (in USD per share)					$ 68.70

Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Less: current maturities	$ (41,276)	$ (297,324)
Long-term debt, less current maturities	4,588,454	4,115,684
Southwest Gas Corporation
Debt Instrument [Line Items]
Less: current maturities	0	(275,000)
Long-term debt, less current maturities	$ 2,904,099	$ 2,440,603
MountainWest unsecured senior notes, 3.53%, due in 2028
Debt Instrument [Line Items]
Debt instrument interest rate	3.53%
MountainWest unsecured senior notes, 4.875%, due in 2041
Debt Instrument [Line Items]
Debt instrument interest rate	4.875%
MountainWest unsecured senior notes, 3.91%, due in 2038
Debt Instrument [Line Items]
Debt instrument interest rate	3.91%
Debentures \| Notes, 6.1%, due 2041 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	6.10%
Debentures \| Notes, 4.05%, due 2032 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	4.05%
Debentures \| Notes, 3.875%, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	3.875%	3.875%
Debentures \| Notes, 4.875%, due 2043 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	4.875%
Debentures \| Notes, 3.8%, due 2046 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	3.80%
Debentures \| Notes, 3.7%, due 2028 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	3.70%
Debentures \| Notes, 4.15%, due 2049 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	4.15%
Debentures \| Notes, 2.2%, due 2030 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	2.20%
Debentures \| Notes, 3.18%, due 2051 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	3.18%
Debentures \| 8% Series, due 2026 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	8.00%
Debentures \| Medium-term notes, 7.78% series, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate		7.78%
Debentures \| Medium-term notes, 7.92% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	7.92%
Debentures \| Medium-term notes, 6.76% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Debt instrument interest rate	6.76%
Carrying Amount
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	$ (22,627)	$ (24,466)
Less: current maturities	(41,276)	(22,324)
Long-term debt, less current maturities	4,588,454	4,115,684
Carrying Amount \| Southwest Gas Corporation
Debt Instrument [Line Items]
Less: current maturities	0	(275,000)
Long-term debt, less current maturities	2,904,099	2,440,603
Carrying Amount \| Centuri secured revolving credit facility \| Centuri
Debt Instrument [Line Items]
Long-term debt, gross	145,885	103,329
Carrying Amount \| Debentures \| Southwest Gas Corporation
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	(26,627)	(19,959)
Long-term debt	2,705,873	2,387,541
Carrying Amount \| Debentures \| Notes, 6.1%, due 2041 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	125,000	125,000
Carrying Amount \| Debentures \| Notes, 4.05%, due 2032 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	600,000	0
Carrying Amount \| Debentures \| Notes, 3.875%, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	0	250,000
Carrying Amount \| Debentures \| Notes, 4.875%, due 2043 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	250,000	250,000
Carrying Amount \| Debentures \| Notes, 3.8%, due 2046 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures \| Notes, 3.7%, due 2028 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures \| Notes, 4.15%, due 2049 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures \| Notes, 2.2%, due 2030 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	450,000	450,000
Carrying Amount \| Debentures \| Notes, 3.18%, due 2051 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures \| 8% Series, due 2026 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	75,000	75,000
Carrying Amount \| Debentures \| Medium-term notes, 7.78% series, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	0	25,000
Carrying Amount \| Debentures \| Medium-term notes, 7.92% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	25,000	25,000
Carrying Amount \| Debentures \| Medium-term notes, 6.76% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	7,500	7,500
Carrying Amount \| Revolving credit facility and commercial paper \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt	0	130,000
Carrying Amount \| Industrial development revenue bonds \| Southwest Gas Corporation
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	(1,774)	(1,938)
Long-term debt	198,226	198,062
Carrying Amount \| Industrial development revenue bonds \| Tax-exempt Series A, due 2028 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds \| 2003 Series A, due 2038 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds \| 2008 Series A, due 2038 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds \| 2009 Series A, due 2039 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Secured Debt \| Centuri secured term loan facility \| Centuri
Debt Instrument [Line Items]
Long-term debt, gross	1,011,413	1,117,138
Carrying Amount \| Unsecured Debt \| MountainWest unsecured senior notes, 3.53%, due in 2028
Debt Instrument [Line Items]
Long-term debt, gross	101,922	102,078
Carrying Amount \| Unsecured Debt \| MountainWest unsecured senior notes, 4.875%, due in 2041
Debt Instrument [Line Items]
Long-term debt, gross	199,599	199,926
Carrying Amount \| Unsecured Debt \| MountainWest unsecured senior notes, 3.91%, due in 2038
Debt Instrument [Line Items]
Long-term debt, gross	147,786	147,735
Carrying Amount \| Other debt obligations
Debt Instrument [Line Items]
Long-term debt, gross	141,653	51,665
Fair Value \| Centuri secured revolving credit facility \| Centuri
Debt Instrument [Line Items]
Long-term debt, gross	145,759	103,749
Fair Value \| Debentures \| Notes, 6.1%, due 2041 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	126,410	166,380
Fair Value \| Debentures \| Notes, 4.05%, due 2032 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	549,396	0
Fair Value \| Debentures \| Notes, 3.875%, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	0	250,603
Fair Value \| Debentures \| Notes, 4.875%, due 2043 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	230,653	307,538
Fair Value \| Debentures \| Notes, 3.8%, due 2046 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	235,140	329,055
Fair Value \| Debentures \| Notes, 3.7%, due 2028 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	283,260	325,191
Fair Value \| Debentures \| Notes, 4.15%, due 2049 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	250,461	342,030
Fair Value \| Debentures \| Notes, 2.2%, due 2030 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	365,054	440,838
Fair Value \| Debentures \| Notes, 3.18%, due 2051 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	211,326	292,116
Fair Value \| Debentures \| 8% Series, due 2026 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	84,078	92,623
Fair Value \| Debentures \| Medium-term notes, 7.78% series, due 2022 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	0	25,122
Fair Value \| Debentures \| Medium-term notes, 7.92% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	27,821	31,555
Fair Value \| Debentures \| Medium-term notes, 6.76% series, due 2027 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	7,839	8,949
Fair Value \| Revolving credit facility and commercial paper \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt	0	130,000
Fair Value \| Industrial development revenue bonds \| Tax-exempt Series A, due 2028 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds \| 2003 Series A, due 2038 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds \| 2008 Series A, due 2038 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds \| 2009 Series A, due 2039 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Secured Debt \| Centuri secured term loan facility \| Centuri
Debt Instrument [Line Items]
Long-term debt, gross	970,329	1,117,841
Fair Value \| Unsecured Debt \| MountainWest unsecured senior notes, 3.53%, due in 2028
Debt Instrument [Line Items]
Long-term debt, gross	90,430	102,078
Fair Value \| Unsecured Debt \| MountainWest unsecured senior notes, 4.875%, due in 2041
Debt Instrument [Line Items]
Long-term debt, gross	157,894	199,926
Fair Value \| Unsecured Debt \| MountainWest unsecured senior notes, 3.91%, due in 2038
Debt Instrument [Line Items]
Long-term debt, gross	113,703	147,735
Fair Value \| Other debt obligations
Debt Instrument [Line Items]
Long-term debt, gross	$ 129,810	$ 50,003

Debt - Narratives (Details)	1 Months Ended	6 Months Ended
Debt - Narratives (Details)	Nov. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) instrument	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Short-term debt		$ 1,462,747,000		$ 1,909,000,000
Negative working capital condition		(707,000,000)
Term Loan Facility Due December 30, 2022 \| Loans Payable
Debt Instrument [Line Items]
Borrowings outstanding under facility		1,150,000,000
Debt instrument face amount	$ 1,600,000,000
Debt instrument, term	364 days
LIBOR
Debt Instrument [Line Items]
Borrowings outstanding under facility		2,160,000,000
Southwest Gas Corporation
Debt Instrument [Line Items]
Short-term debt		225,000,000		$ 250,000,000
Southwest Gas Corporation \| March 2021 Term Loan
Debt Instrument [Line Items]
Borrowings outstanding under facility		225,000,000
Debt instrument face amount			$ 250,000,000
Southwest Gas Corporation \| Debentures \| Notes, 4.05%, due 2032
Debt Instrument [Line Items]
Debt instrument face amount		$ 600,000,000
Debt instrument interest rate		4.05%
Debt instrument discount rate		0.65%
Southwest Gas Corporation \| Debentures \| Notes, 3.875%, due 2022
Debt Instrument [Line Items]
Debt instrument face amount		$ 250,000,000
Debt instrument interest rate		3.875%		3.875%
Southwest Gas Corporation \| LIBOR
Debt Instrument [Line Items]
Borrowings outstanding under facility		$ 0
Centuri \| Centuri secured term loan facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		1,145,000,000
Centuri \| Centuri Secured Term Loan Facility And Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		1,545,000,000
Borrowings outstanding under facility		1,157,000,000
Debt secured by assets		$ 2,500,000,000
MountainWest
Debt Instrument [Line Items]
Number of private placement \| instrument		2
MountainWest \| Unsecured Debt
Debt Instrument [Line Items]
Debt instrument face amount		$ 430,000,000
Long-term debt, gross		449,300,000
$400 Million Credit Facility \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		400,000,000
Line of credit designated as long term debt		150,000,000
Line of credit designated for working capital purposes		250,000,000
Long-term debt outstanding		0
Short-term debt		$ 0
$400 Million Credit Facility \| Southwest Gas Corporation \| SOFR
Debt Instrument [Line Items]
Debt, basis spread on variable rate		1.125%
$400 Million Credit Facility \| Southwest Gas Corporation \| Alternative base rate
Debt Instrument [Line Items]
Debt, basis spread on variable rate		0.125%
Commercial Paper Program \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 50,000,000
Borrowings outstanding under facility		0
Centuri secured revolving credit facility \| Centuri \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		400,000,000
$100 Million Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		200,000,000
Borrowings outstanding under facility		$ 90,000,000

Other Comprehensive Income and Accumulated Other Comprehensive Income - Related Tax Effects Allocated to OCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	$ (1,200)	$ 3,266	$ 2,073	$ 6,447	$ 14,358	$ (1,877)
Other comprehensive income (loss), tax	(356)	(566)	(840)	(1,132)	(4,198)	1,806
Total other comprehensive income (loss), net of tax	(1,556)	2,700	1,233	$ 5,315	10,160	(71)
Other comprehensive income (loss) before reclassifications, net of tax			$ (1,433)
Effective income tax rate			24.00%	24.00%
Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	1,480	2,357	$ 3,506	$ 4,715	17,503	(7,533)
Other comprehensive income (loss), tax	(356)	(566)	(840)	(1,132)	(4,198)	1,806
Total other comprehensive income (loss), net of tax	1,124	1,791	2,666	3,583	13,305	(5,727)
Pension plans other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	1,480	1,813	2,961	3,627	15,872	(10,195)
Other comprehensive income (loss), tax	(356)	(436)	(711)	(871)	(3,808)	2,445
Total other comprehensive income (loss), net of tax	1,124	1,377	2,250	2,756	12,064	(7,750)
Pension plans other comprehensive income (loss) \| Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax			2,961
Other comprehensive income (loss), tax			(711)
Total other comprehensive income (loss), net of tax			2,250
Amortization of prior service cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before Tax	44	240	88	480	567	1,057
Reclassification from AOCI, tax	(11)	(58)	(22)	(116)	(136)	(255)
Reclassification from AOCI, net of tax	33	182	66	364	431	802
Other comprehensive income (loss), before tax			88
Other comprehensive income (loss), tax			(22)
Total other comprehensive income (loss), net of tax			66
Amortization of prior service cost \| Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax			88
Other comprehensive income (loss), tax			(22)
Total other comprehensive income (loss), net of tax			66
Amortization of net actuarial (gain)/loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before Tax	8,704	11,148	17,409	22,297	39,709	41,212
Reclassification from AOCI, tax	(2,089)	(2,676)	(4,178)	(5,351)	(9,530)	(9,890)
Reclassification from AOCI, net of tax	6,615	8,472	13,231	16,946	30,179	31,322
Other comprehensive income (loss), before tax			17,409
Other comprehensive income (loss), tax			(4,178)
Total other comprehensive income (loss), net of tax			13,231
Other comprehensive income (loss) before reclassifications, before tax					59,176	(57,539)
Other comprehensive income (loss) before reclassifications, tax					(14,202)	13,809
Other comprehensive income (loss) before reclassifications, net of tax					44,974	(43,730)
Amortization of net actuarial (gain)/loss \| Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax			17,409
Other comprehensive income (loss), tax			(4,178)
Total other comprehensive income (loss), net of tax			13,231
Regulatory adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before Tax	(7,268)	(9,575)	(14,536)	(19,150)	(83,580)	5,075
Reclassification from AOCI, tax	1,744	2,298	3,489	4,596	20,060	(1,219)
Reclassification from AOCI, net of tax	(5,524)	(7,277)	(11,047)	(14,554)	(63,520)	3,856
Other comprehensive income (loss), before tax			(14,536)
Other comprehensive income (loss), tax			3,489
Total other comprehensive income (loss), net of tax			(11,047)
Regulatory adjustment \| Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax			(14,536)
Other comprehensive income (loss), tax			3,489
Total other comprehensive income (loss), net of tax			(11,047)
FSIRS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before Tax	0	544	545	1,088	1,631	2,662
Reclassification from AOCI, tax	0	(130)	(129)	(261)	(390)	(639)
Reclassification from AOCI, net of tax	0	414	416	827	1,241	2,023
Other comprehensive income (loss), before tax	0	544	545	1,088	1,631	2,662
Other comprehensive income (loss), tax	0	(130)	(129)	(261)	(390)	(639)
Total other comprehensive income (loss), net of tax	0	414	416	827	1,241	2,023
FSIRS \| Southwest Gas Corporation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before Tax			545
Reclassification from AOCI, tax			(129)
Reclassification from AOCI, net of tax			416
Other comprehensive income (loss), before tax			545
Other comprehensive income (loss), tax			(129)
Total other comprehensive income (loss), net of tax			416
Foreign currency items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, before tax	(2,680)	909	(1,433)	1,732	(3,145)	5,656
Other comprehensive income (loss) before reclassifications, tax	0	0	0	0	0	0
Other comprehensive income (loss) before reclassifications, net of tax	$ (2,680)	$ 909	$ (1,433)	$ 1,732	$ (3,145)	$ 5,656

Other Comprehensive Income and Accumulated Other Comprehensive Income - AOCI Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, attributable to parent			$ 2,953,820
Other comprehensive income (loss) before reclassifications, net of tax			(1,433)
Other comprehensive income (loss), before tax	$ (1,200)	$ 3,266	2,073	$ 6,447	$ 14,358	$ (1,877)
Other comprehensive income (loss), tax	(356)	(566)	(840)	(1,132)	(4,198)	1,806
Total other comprehensive income (loss), net of tax	(1,556)	2,700	1,233	$ 5,315	10,160	(71)
Ending balance, attributable to parent	3,458,852		$ 3,458,852		3,458,852
Effective income tax rate			24.00%	24.00%
Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance					2,429,736
Beginning balance, attributable to parent			$ 2,527,937
Other comprehensive income (loss), before tax	1,480	2,357	3,506	$ 4,715	17,503	(7,533)
Other comprehensive income (loss), tax	(356)	(566)	(840)	(1,132)	(4,198)	1,806
Total other comprehensive income (loss), net of tax	1,124	1,791	2,666	3,583	13,305	(5,727)
Ending balance	2,579,596	2,429,736	2,579,596	2,429,736	2,579,596	2,429,736
Ending balance, attributable to parent	2,579,596		2,579,596		2,579,596
Defined Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, before tax			(61,182)
Beginning balance, tax			14,685
Beginning balance			(46,497)
Other comprehensive income (loss), before tax	1,480	1,813	2,961	3,627	15,872	(10,195)
Other comprehensive income (loss), tax	(356)	(436)	(711)	(871)	(3,808)	2,445
Total other comprehensive income (loss), net of tax	1,124	1,377	2,250	2,756	12,064	(7,750)
Ending balance, before tax	(58,221)		(58,221)		(58,221)
Ending balance, tax	13,974		13,974		13,974
Ending balance	(44,247)		(44,247)		(44,247)
Defined Benefit Plans \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, attributable to parent, before tax			(61,182)
Beginning balance, attributable to parent, tax			14,685
Beginning balance, attributable to parent			(46,497)
Other comprehensive income (loss), before tax			2,961
Other comprehensive income (loss), tax			(711)
Total other comprehensive income (loss), net of tax			2,250
Ending balance, attributable to parent, before tax	(58,221)		(58,221)		(58,221)
Ending balance, attributable to parent, tax	13,974		13,974		13,974
Ending balance, attributable to parent	(44,247)		(44,247)		(44,247)
Amortization of prior service cost
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from AOCI, before Tax	44	240	88	480	567	1,057
Reclassification from AOCI, tax	(11)	(58)	(22)	(116)	(136)	(255)
Reclassification from AOCI, net of tax	33	182	66	364	431	802
Other comprehensive income (loss), before tax			88
Other comprehensive income (loss), tax			(22)
Total other comprehensive income (loss), net of tax			66
Amortization of prior service cost \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before tax			88
Other comprehensive income (loss), tax			(22)
Total other comprehensive income (loss), net of tax			66
Amortization of net actuarial loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications, before tax					59,176	(57,539)
Other comprehensive income (loss) before reclassifications, net of tax					44,974	(43,730)
Reclassification from AOCI, before Tax	8,704	11,148	17,409	22,297	39,709	41,212
Reclassification from AOCI, tax	(2,089)	(2,676)	(4,178)	(5,351)	(9,530)	(9,890)
Reclassification from AOCI, net of tax	6,615	8,472	13,231	16,946	30,179	31,322
Other comprehensive income (loss), before tax			17,409
Other comprehensive income (loss), tax			(4,178)
Total other comprehensive income (loss), net of tax			13,231
Amortization of net actuarial loss \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before tax			17,409
Other comprehensive income (loss), tax			(4,178)
Total other comprehensive income (loss), net of tax			13,231
Regulatory adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from AOCI, before Tax	(7,268)	(9,575)	(14,536)	(19,150)	(83,580)	5,075
Reclassification from AOCI, tax	1,744	2,298	3,489	4,596	20,060	(1,219)
Reclassification from AOCI, net of tax	(5,524)	(7,277)	(11,047)	(14,554)	(63,520)	3,856
Other comprehensive income (loss), before tax			(14,536)
Other comprehensive income (loss), tax			3,489
Total other comprehensive income (loss), net of tax			(11,047)
Regulatory adjustment \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before tax			(14,536)
Other comprehensive income (loss), tax			3,489
Total other comprehensive income (loss), net of tax			(11,047)
FSIRS
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, before tax			(545)
Beginning balance, tax			129
Beginning balance			(416)
Reclassification from AOCI, before Tax	0	544	545	1,088	1,631	2,662
Reclassification from AOCI, tax	0	(130)	(129)	(261)	(390)	(639)
Reclassification from AOCI, net of tax	0	414	416	827	1,241	2,023
Other comprehensive income (loss), before tax	0	544	545	1,088	1,631	2,662
Other comprehensive income (loss), tax	0	(130)	(129)	(261)	(390)	(639)
Total other comprehensive income (loss), net of tax	0	414	416	827	1,241	2,023
Ending balance, before tax	0		0		0
Ending balance, tax	0		0		0
Ending balance	0		0		0
FSIRS \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, attributable to parent, before tax			(545)
Beginning balance, attributable to parent, tax			129
Beginning balance, attributable to parent			(416)
Reclassification from AOCI, before Tax			545
Reclassification from AOCI, tax			(129)
Reclassification from AOCI, net of tax			416
Other comprehensive income (loss), before tax			545
Other comprehensive income (loss), tax			(129)
Total other comprehensive income (loss), net of tax			416
Ending balance, attributable to parent, before tax	0		0		0
Ending balance, attributable to parent, tax	0		0		0
Ending balance, attributable to parent	0		0		0
Foreign Currency Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, before tax			152
Beginning balance, tax			0
Beginning balance			152
Other comprehensive income (loss) before reclassifications, before tax			(1,433)
Other comprehensive income (loss) before reclassifications, net of tax			(1,433)
Ending balance, before tax	(1,281)		(1,281)		(1,281)
Ending balance, tax	0		0		0
Ending balance	(1,281)		(1,281)		(1,281)
AOCI Including Portion Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications, net of tax			1,233
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(43,972)	(58,388)	(46,761)	(61,003)	(55,688)
Ending balance	(45,528)	(55,688)	(45,528)	(55,688)	(45,528)	(55,688)
AOCI Attributable to Parent \| Southwest Gas Corporation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(45,371)	(59,343)	(46,913)	(61,135)	(57,552)
Beginning balance, attributable to parent			(46,913)
Ending balance	(44,247)	$ (57,552)	(44,247)	$ (57,552)	(44,247)	$ (57,552)
Ending balance, attributable to parent	$ (44,247)		$ (44,247)		$ (44,247)

Other Comprehensive Income and Accumulated Other Comprehensive Income - Amounts Recognized Before Tax, Defined Benefit Plans (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Equity [Abstract]
Net actuarial loss	$ (381,601)	$ (399,010)
Prior service cost	(1,440)	(1,528)
Less: amount recognized in regulatory assets	324,820	339,356
Recognized in AOCI	$ (58,221)	$ (61,182)

Segment Information - Narratives (Details) - segment	6 Months Ended	12 Months Ended
Segment Information - Narratives (Details) - segment	Jun. 30, 2022	Dec. 31, 2021
Segment Reporting [Abstract]
Number of reportable segments	3	2

Segment Information - Accounts Receivable Not Eliminated During Consolidation (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Centuri
Segment Reporting Information [Line Items]
Centuri accounts receivable for services provided to Southwest	$ 16,915	$ 15,166

- Definition

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(C))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124098289&loc=d3e6676-107765

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(B))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(2))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(1))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Total Regulated operations revenues	$ 1,146,120	$ 821,421	$ 2,413,529	$ 1,707,328	$ 4,386,652	$ 3,412,634
Segment net income (loss)	(6,575)	25,119	89,603	142,412	147,970	264,229
Revenues from external customers
Segment Reporting Information [Line Items]
Total Regulated operations revenues	1,112,149	797,737	2,351,225	1,659,441	4,269,889	3,300,013
Intersegment revenues
Segment Reporting Information [Line Items]
Total Regulated operations revenues	33,971	23,684	62,304	47,887	116,763	112,621
Segment net income (loss)	(24,126)	(1,410)	(33,187)	(1,973)	(57,990)	(2,532)
Natural Gas Distribution
Segment Reporting Information [Line Items]
Total Regulated operations revenues	377,942	292,796	1,054,481	814,728	1,761,543	1,400,052
Segment net income (loss)	(2,266)	11,413	109,529	130,128	166,536	193,705
Natural Gas Distribution \| Revenues from external customers
Segment Reporting Information [Line Items]
Total Regulated operations revenues	377,942	292,796	1,054,481	814,728	1,761,543	1,400,052
Natural Gas Distribution \| Intersegment revenues
Segment Reporting Information [Line Items]
Total Regulated operations revenues	0	0	0	0	0	0
Utility Infrastructure Services
Segment Reporting Information [Line Items]
Total Regulated operations revenues	706,090	528,625	1,229,967	892,600	2,496,028	2,012,582
Segment net income (loss)	4,741	15,116	(18,745)	14,257	7,418	73,056
Utility Infrastructure Services \| Revenues from external customers
Segment Reporting Information [Line Items]
Total Regulated operations revenues	672,119	504,941	1,167,663	844,713	2,379,265	1,899,961
Utility Infrastructure Services \| Intersegment revenues
Segment Reporting Information [Line Items]
Total Regulated operations revenues	33,971	23,684	62,304	47,887	116,763	112,621
Pipeline and Storage
Segment Reporting Information [Line Items]
Total Regulated operations revenues	62,088	0	129,081	0	129,081	0
Segment net income (loss)	15,076	0	32,006	0	32,006	0
Pipeline and Storage \| Revenues from external customers
Segment Reporting Information [Line Items]
Total Regulated operations revenues	62,088	0	129,081	0	129,081	0
Pipeline and Storage \| Intersegment revenues
Segment Reporting Information [Line Items]
Total Regulated operations revenues	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details

Business Acquisitions - Narrative (Detail) - USD ($)	3 Months Ended	6 Months Ended
Business Acquisitions - Narrative (Detail) - USD ($)	Jun. 30, 2022	Jun. 30, 2022	Nov. 30, 2021
Business Acquisition [Line Items]
Incurred and expensed acquisition costs	$ 18,500,000	$ 18,500,000
Drum
Business Acquisition [Line Items]
Incurred and expensed acquisition costs	14,000,000	14,000,000
Acquisition-related costs	0	$ 0
Questar Pipelines
Business Acquisition [Line Items]
Acquisition-related costs	$ 0
Certain Members Of Riggs Distler Management \| Drum
Business Acquisition [Line Items]
Ownership percentage by noncontrolling owners	1.42%	1.42%	1.42%

Business Acquisitions - Summary of Assets Acquired and Liabilities Assumed - Drum Acquisition (Detail) - USD ($) $ in Thousands	10 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Aug. 27, 2021
Fair Values of Assets Acquired and Liabilities Assumed
Goodwill	$ 1,750,472	$ 1,781,332
Drum
Fair Values of Assets Acquired and Liabilities Assumed
Cash and cash equivalents	1,900		$ 1,900
Accounts receivable	60,500		69,100
Contract assets	47,500		40,100
Income taxes receivable, net	700		700
Right of use assets under operating leases	1,500		1,500
Prepaid expenses	5,200		5,200
Property and equipment	119,300		118,100
Intangible assets	303,500		335,000
Goodwill	448,600		446,800
Total assets acquired	988,700		1,018,400
Trade and other payables	46,200		46,200
Finance lease obligations	28,700		27,500
Contract liabilities	12,700		12,700
Operating lease obligations	1,500		1,500
Other liabilities	4,100		5,300
Deferred tax liabilities	71,400		94,800
Total liabilities assumed and noncontrolling interest	164,600		188,000
Net assets acquired	824,100		$ 830,400
Measurement Period Adjustments, Accounts receivable	(8,600)
Measurement Period Adjustments, Contract assets	7,400
Measurement Period Adjustments, Property and equipment	1,200
Measurement Period Adjustments, Intangible assets	(31,500)
Measurement Period Adjustments, Goodwill	1,800
Measurement Period Adjustments, Total assets	(29,700)
Measurement Period Adjustments, Finance lease obligations	1,200
Measurement Period Adjustments, Other liabilities	(1,200)
Measurement Period Adjustments, Deferred tax liabilities	(23,400)
Measurement Period Adjustments, Total liabilities	(23,400)
Measurement Period Adjustments, Net assets acquired	$ (6,300)

Business Acquisitions - Summary of Assets Acquired and Liabilities Assumed - Questar Acquisition (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill	$ 1,750,472	$ 1,781,332
Questar Pipelines
Business Acquisition [Line Items]
Gas plant, net	1,047,400	1,047,400
Other property and investments	51,300	51,300
Cash and cash equivalents	17,600	17,600
Accounts receivable	29,500	26,600
Prepaid and other current assets	27,400	27,400
Deferred charges and other assets	31,100	31,100
Goodwill	958,000	986,200
Deferred income taxes, net	36,300	15,400
Total assets acquired	2,198,600	2,203,000
Long-term debt	449,700	449,700
Accounts payable	7,000	7,000
Deferred purchased gas costs	5,700	5,700
Customer deposits	3,200	3,200
Accrued general taxes	400	400
Accrued interest	4,700	4,700
Other current liabilities	14,500	14,500
Accumulated removal costs	56,600	56,600
Other deferred credits	85,600	85,600
Total liabilities assumed and noncontrolling interest	627,400	627,400
Net assets acquired	1,571,200	$ 1,575,600
Measurement Period Adjustments, Accounts receivable, net of allowances	2,900
Measurement Period Adjustments, Goodwill	(28,200)
Measurement Period Adjustments, Deferred income taxes	20,900
Measurement Period Adjustments, Total assets	(4,400)
Measurement Period Adjustments, Net assets acquired	$ (4,400)