CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
CURRENT ASSETS
Cash and cash equivalents	$ 4,832	$ 9,969
Customer and other receivables	453,209	391,923
Accrued unbilled revenues	164,764	133,980
Allowance for doubtful accounts (Note 2)	(23,778)	(25,354)
Materials and supplies (at average cost)	410,481	349,135
Fossil fuel (at average cost)	40,155	18,032
Income tax receivable (Note 4)	14,086	7,514
Assets from risk management activities (Note 15)	87,835	63,481
Deferred fuel and purchased power regulatory asset (Note 3)	460,561	388,148
Other regulatory assets (Note 3)	78,318	130,376
Other current assets	60,091	83,896
Total current assets	1,750,554	1,551,100
INVESTMENTS AND OTHER ASSETS
Nuclear decommissioning trusts (Notes 12 and 18)	1,073,410	1,294,757
Other special use funds (Notes 12 and 18)	347,231	358,410
Assets from risk management activities (Note 15)	44,394	46,908
Other assets	125,672	97,884
Total investments and other assets	1,590,707	1,797,959
PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6 and 9)
Plant in service and held for future use	22,452,146	21,688,661
Accumulated depreciation and amortization	(7,929,878)	(7,504,603)
Net	14,522,268	14,184,058
Construction work in progress	1,882,791	1,329,478
Palo Verde sale leaseback, net of accumulated depreciation of $260,754 and $256,884 (Note 17)	90,296	94,166
Intangible assets, net of accumulated amortization of $817,961 and $737,694	258,880	273,693
Nuclear fuel, net of accumulated amortization of $126,157 and $133,122	100,119	106,039
Total property, plant and equipment	16,854,354	15,987,434
DEFERRED DEBITS
Regulatory assets (Notes 1, 3 and 4)	1,283,221	1,192,987
Operating lease right-of-use assets (Note 8)	801,688	890,057
Assets for pension and other postretirement benefits (Note 7)	396,599	545,723
Other	46,282	37,962
Total deferred debits	2,527,790	2,666,729
TOTAL ASSETS	22,723,405	22,003,222
CURRENT LIABILITIES
Accounts payable	430,425	393,083
Accrued taxes	164,440	168,645
Accrued interest	61,217	57,332
Common dividends payable	97,895	95,988
Short-term borrowings (Note 5)	340,720	292,000
Current maturities of long-term debt (Note 6)	50,685	150,000
Customer deposits	41,769	42,293
Liabilities from risk management activities (Note 15)	37,697	4,373
Liabilities for asset retirements (Note 11)	12,232	4,473
Operating lease liabilities (Note 8)	105,210	100,443
Less: current regulatory liabilities	271,575	296,271
Other current liabilities	148,276	151,968
Total current liabilities	1,762,141	1,756,869
LONG-TERM DEBT LESS CURRENT MATURITIES (Note 6)	7,741,286	6,913,735
DEFERRED CREDITS AND OTHER
Deferred income taxes (Note 4)	2,384,421	2,311,862
Regulatory liabilities (Notes 1, 3, 4 and 7)	2,061,776	2,499,213
Liabilities for asset retirements (Note 11)	785,530	762,909
Liabilities for pension benefits (Note 7)	116,286	152,865
Customer advances	422,103	257,151
Coal mine reclamation	179,255	174,616
Deferred investment tax credit	180,677	186,570
Unrecognized tax benefits (Note 4)	38,658	4,657
Operating lease liabilities (Note 8)	639,247	728,401
Other	252,149	232,914
Total deferred credits and other	7,060,102	7,311,158
COMMITMENTS AND CONTINGENCIES (SEE NOTES)
EQUITY
Common stock, no par value; authorized 150,000,000 shares, 113,247,189 and 113,014,528 issued at respective dates	2,724,740	2,702,743
Treasury stock at cost; 73,613 and 87,608 shares at respective dates	(5,005)	(6,401)
Total common stock	2,719,735	2,696,342
Retained earnings	3,360,347	3,264,719
Accumulated other comprehensive loss (Note 19)	(31,435)	(54,861)
Total shareholders’ equity	6,048,647	5,906,200
Noncontrolling interests (Note 17)	111,229	115,260
Total equity	6,159,876	6,021,460
TOTAL LIABILITIES AND EQUITY	$ 22,723,405	$ 22,003,222