CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	$ 47,650	$ 97,250	$ (247,284)	$ 185,607
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	112,520	122,646	460,329	400,245
Impairment of assets and other charges	71,230	0	526,655	0
Deferred income taxes	36,712	32,346	(67,682)	70,232
Gains on sale of property and equipment	(661)	(1,916)	(6,610)	(7,313)
Changes in undistributed stock compensation	3,436	4,180	8,702	9,816
Equity AFUDC	(82)	(258)	(289)	723
Changes in current assets and liabilities:
Accounts receivable, net of allowances	(40,185)	(44,971)	(188,989)	(139,417)
Accrued utility revenue	31,200	32,900	(4,900)	(1,500)
Deferred purchased gas costs	(535,224)	(82,248)	(600,191)	(134,507)
Accounts payable	(305,272)	(82,952)	71,589	8,621
Accrued taxes	34,950	33,964	18,915	(7,397)
Other current assets and liabilities	371,035	79,680	83,502	(4,274)
Changes in deferred charges and other assets	(1,565)	(297)	15,618	(3,459)
Changes in other liabilities and deferred credits	(11,486)	(3,704)	(34,267)	(26,917)
Net cash provided by (used in) operating activities	(185,742)	186,620	35,098	350,460
CASH FLOW FROM INVESTING ACTIVITIES:
Construction expenditures and property additions	(219,124)	(162,796)	(915,749)	(725,713)
Acquisition of businesses, net of cash acquired	0	0	(18,809)	(2,354,260)
Proceeds from the sale of business, net of cash sold	1,058,272	0	1,058,272	0
Changes in customer advances	(6,608)	7,693	7,205	19,381
Other	3,125	893	20,054	15,586
Net cash provided by (used in) investing activities	835,665	(154,210)	150,973	(3,045,006)
CASH FLOW FROM FINANCING ACTIVITIES:
Issuance of common stock, net	239,337	453,495	247,670	618,146
Centuri distribution to redeemable noncontrolling interest	0	(39,649)	0	(39,649)
Dividends paid	(41,631)	(35,970)	(166,224)	(141,573)
Issuance of long-term debt, net	305,896	709,927	663,774	2,359,964
Retirement of long-term debt	(84,224)	(143,453)	(440,685)	(574,889)
Change in credit facility and commercial paper	(50,000)	(130,000)	0	(150,000)
Change in short-term debt	(1,527,746)	(435,000)	(1,458,939)	(686,000)
Issuance of short-term debt	450,000	0	450,000	1,850,000
Withholding remittance - share-based compensation	(1,506)	(1,978)	(2,190)	(2,000)
Other, including principal payments on finance leases	(4,949)	(7,898)	(21,223)	(7,274)
Net cash provided by (used in) financing activities	(714,823)	369,474	(727,817)	3,226,725
Effects of currency translation on cash and cash equivalents	104	85	(835)	142
Change in cash and cash equivalents	(64,796)	401,969	(542,581)	532,321
Cash and cash equivalents included in current assets held for sale at beginning of period		0		0
Cash and cash equivalents at beginning of period	123,078	222,697	624,666	92,345
Cash and cash equivalents at end of period	82,085	624,666	82,085	624,666
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	68,018	35,262	252,581	131,311
Income taxes paid, net	$ 2,381	$ 1,408	$ 12,974	$ 3,965