CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
CURRENT ASSETS
Cash and cash equivalents	$ 49,171	$ 4,955
Customer and other receivables	839,094	513,892
Accrued unbilled revenues (Note 2)	261,841	167,553
Allowance for doubtful accounts (Note 2)	(18,347)	(22,433)
Materials and supplies (at average cost)	473,847	444,344
Income tax receivable	0	332
Fossil fuel (at average cost)	54,193	49,203
Assets from risk management activities (Note 7)	641	6,808
Assets held for sale (Note 16)	0	35,139
Deferred fuel and purchased power regulatory asset (Note 4)	367,274	463,195
Other regulatory assets (Note 4)	150,093	162,562
Other current assets	86,759	101,417
Total current assets	2,264,566	1,926,967
INVESTMENTS AND OTHER ASSETS
Nuclear decommissioning trusts (Notes 11 and 12)	1,300,012	1,201,246
Other special use funds (Notes 11 and 12)	387,499	362,781
Other assets	122,359	102,845
Total investments and other assets	1,809,870	1,666,872
PROPERTY, PLANT AND EQUIPMENT
Plant in service and held for future use	25,262,439	24,211,167
Accumulated depreciation and amortization	(8,877,815)	(8,408,040)
Net	16,384,624	15,803,127
Construction work in progress	1,713,379	1,724,004
Palo Verde sale leaseback, net of accumulated depreciation (Note 6)	83,524	86,426
Intangible assets, net of accumulated amortization	586,559	267,110
Nuclear fuel, net of accumulated amortization	112,135	99,490
Total property, plant and equipment	18,880,221	17,980,157
DEFERRED DEBITS
Regulatory assets (Note 4)	1,345,777	1,390,279
Operating lease right-of-use assets (Note 14)	1,599,800	1,309,975
Assets for pension and other postretirement benefits (Note 5)	351,546	323,438
Other	57,774	63,465
Total deferred debits	3,354,897	3,087,157
TOTAL ASSETS	26,309,554	24,661,153
CURRENT LIABILITIES
Accounts payable	429,478	442,455
Accrued taxes	341,640	166,833
Accrued interest	83,910	72,916
Common dividends payable	0	99,813
Short-term borrowings (Note 3)	623,500	609,500
Current maturities of long-term debt (Note 3)	1,000,000	875,000
Customer deposits	41,976	42,037
Liabilities from risk management activities (Note 7)	79,617	80,913
Liabilities for asset retirements (Note 15)	52,185	28,550
Operating lease liabilities (Note 14)	119,080	67,883
Regulatory liabilities (Note 4)	243,714	209,923
Other current liabilities	182,246	193,524
Total current liabilities	3,197,346	2,889,347
LONG-TERM DEBT LESS CURRENT MATURITIES (Note 3)	8,056,318	7,540,622
DEFERRED CREDITS AND OTHER
Deferred income taxes	2,453,968	2,416,480
Regulatory liabilities (Note 4)	1,809,563	1,965,865
Liabilities for asset retirements (Note 15)	1,099,223	937,451
Liabilities for pension benefits (Note 5)	107,355	112,702
Liabilities from risk management activities (Note 7)	28,915	42,975
Customer advances	601,910	533,580
Coal mine reclamation	187,673	184,007
Deferred investment tax credit	247,456	257,743
Unrecognized tax benefits	44,564	33,861
Operating lease liabilities (Note 14)	1,517,058	1,210,189
Other	232,135	251,469
Total deferred credits and other	8,329,820	7,946,322
COMMITMENTS AND CONTINGENCIES (Note 8)
EQUITY
Common stock, no par value; authorized 150,000,000 shares, 113,735,926 and 113,537,689 issued at respective dates	2,774,505	2,752,676
Treasury stock at cost; 101,641 and 113,272 shares at respective dates	(7,191)	(8,185)
Total common stock	2,767,314	2,744,491
Retained earnings	3,882,081	3,466,317
Accumulated other comprehensive loss (Note 13)	(32,814)	(33,144)
Total shareholder equity	6,616,581	6,177,664
Noncontrolling interests (Note 6)	109,489	107,198
Total equity	6,726,070	6,284,862
TOTAL LIABILITIES AND EQUITY	$ 26,309,554	$ 24,661,153