CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
CURRENT ASSETS
Cash and cash equivalents	$ 29,189	$ 9,969
Customer and other receivables	420,288	391,923
Accrued unbilled revenues	234,523	133,980
Allowance for doubtful accounts (Note 2)	(23,147)	(25,354)
Materials and supplies (at average cost)	371,655	349,135
Income tax receivable	0	7,514
Fossil fuel (at average cost)	29,827	18,032
Assets from risk management activities (Note 7)	137,028	63,481
Deferred fuel and purchased power regulatory asset (Note 4)	390,013	388,148
Other regulatory assets (Note 4)	119,163	130,376
Other current assets	89,609	83,896
Total current assets	1,798,148	1,551,100
INVESTMENTS AND OTHER ASSETS
Nuclear decommissioning trusts (Notes 11 and 12)	1,076,088	1,294,757
Other special use funds (Notes 11 and 12)	346,406	358,410
Assets from risk management activities (Note 7)	111,847	46,908
Other assets	117,573	97,884
Total investments and other assets	1,651,914	1,797,959
PROPERTY, PLANT AND EQUIPMENT
Plant in service and held for future use	22,167,179	21,688,661
Accumulated depreciation and amortization	(7,667,678)	(7,504,603)
Net	14,499,501	14,184,058
Construction work in progress	1,386,113	1,329,478
Palo Verde sale leaseback, net of accumulated depreciation (Note 6)	92,231	94,166
Intangible assets, net of accumulated amortization	265,662	273,693
Nuclear fuel, net of accumulated amortization	132,696	106,039
Total property, plant and equipment	16,376,203	15,987,434
DEFERRED DEBITS
Regulatory assets (Note 4)	1,180,656	1,192,987
Operating lease right-of-use assets	871,480	890,057
Assets for pension and other postretirement benefits (Note 5)	577,399	545,723
Other	45,680	37,962
Total deferred debits	2,675,215	2,666,729
TOTAL ASSETS	22,501,480	22,003,222
CURRENT LIABILITIES
Accounts payable	436,308	393,083
Accrued taxes	181,927	168,645
Accrued interest	57,349	57,332
Common dividends payable	96,081	95,988
Short-term borrowings (Note 3)	541,000	292,000
Current maturities of long-term debt (Note 3)	0	150,000
Customer deposits	41,459	42,293
Liabilities from risk management activities (Note 7)	5,596	4,373
Liabilities for asset retirements	5,111	4,473
Operating lease liabilities	125,320	100,443
Regulatory liabilities (Note 4)	404,107	296,271
Other current liabilities	128,190	151,968
Total current liabilities	2,022,448	1,756,869
LONG-TERM DEBT LESS CURRENT MATURITIES (Note 3)	7,241,295	6,913,735
DEFERRED CREDITS AND OTHER
Deferred income taxes	2,357,469	2,311,862
Regulatory liabilities (Note 4)	2,268,148	2,499,213
Liabilities for asset retirements	779,360	762,909
Liabilities for pension benefits (Note 5)	150,837	152,865
Customer advances	336,198	257,151
Coal mine reclamation	176,936	174,616
Deferred investment tax credit	184,032	186,570
Unrecognized tax benefits	4,896	4,657
Operating lease liabilities	710,511	728,401
Other	247,827	232,914
Total deferred credits and other	7,216,214	7,311,158
COMMITMENTS AND CONTINGENCIES (Note 8)
EQUITY
Common stock, no par value; authorized 150,000,000 shares, 113,078,049 and 113,014,528 issued at respective dates	2,712,297	2,702,743
Treasury stock at cost; 41,531 and 87,608 shares at respective dates	(2,976)	(6,401)
Total common stock	2,709,321	2,696,342
Retained earnings	3,253,772	3,264,719
Accumulated other comprehensive loss (Note 13)	(54,814)	(54,861)
Total shareholders’ equity	5,908,279	5,906,200
Noncontrolling interests (Note 6)	113,244	115,260
Total equity	6,021,523	6,021,460
TOTAL LIABILITIES AND EQUITY	$ 22,501,480	$ 22,003,222