CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME	$ 584,570	$ 488,959
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization including nuclear fuel	515,742	500,801
Deferred fuel and purchased power	(82,679)	(60,911)
Deferred fuel and purchased power amortization	(9,295)	38,601
Allowance for equity funds used during construction	(24,652)	(24,677)
Deferred income taxes	91,077	83,703
Deferred investment tax credit	(8,541)	(7,288)
Stock compensation	12,119	16,486
Customer and other receivables	(118,998)	(91,506)
Changes in current assets and liabilities:
Accrued unbilled revenues	(47,176)	(18,666)
Materials, supplies and fossil fuel	6,843	(18,332)
Income tax receivable	17,402	(14,063)
Other current assets	(20,527)	(10,104)
Accounts payable	(6,400)	33,899
Accrued taxes	76,459	66,111
Other current liabilities	6,946	(68,927)
Change in other long-term assets	(10,152)	(52,276)
Change in other long-term liabilities	(210,719)	(27,049)
Net cash flow provided by operating activities	772,019	834,761
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(971,052)	(857,883)
Contributions in aid of construction	41,457	34,121
Allowance for borrowed funds used during construction	(13,488)	(14,645)
Proceeds from nuclear decommissioning trust sales and other special use funds	607,885	520,996
Investment in nuclear decommissioning trust and other special use funds	(624,249)	(523,573)
Other	3,944	8,971
Net cash flow used for investing activities	(955,503)	(832,013)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of long-term debt	1,483,822	794,981
Short-term borrowing and payments — net	(42,750)	(6,025)
Short-term debt borrowings	751,690	49,000
Short-term debt repayments	(765,690)	(62,000)
Repayment of long-term debt	(800,000)	(500,000)
Dividends paid on common stock	(258,924)	(243,116)
Common stock equity issuance - net of purchases	(1,649)	(130)
Distributions to noncontrolling interests	(11,372)	(11,372)
Net cash flow provided by financing activities	355,127	21,338
NET INCREASE IN CASH AND CASH EQUIVALENTS	171,643	24,086
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	10,283	5,766
CASH AND CASH EQUIVALENTS AT END OF PERIOD	181,926	29,852
APS
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME	597,446	511,942
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization including nuclear fuel	515,679	500,737
Deferred fuel and purchased power	(82,679)	(60,911)
Deferred fuel and purchased power amortization	(9,295)	38,601
Allowance for equity funds used during construction	(24,652)	(24,677)
Deferred income taxes	52,795	97,002
Deferred investment tax credit	(8,541)	(7,288)
Customer and other receivables	(129,892)	(90,817)
Changes in current assets and liabilities:
Accrued unbilled revenues	(47,176)	(18,666)
Materials, supplies and fossil fuel	6,843	(18,332)
Income tax receivable	7,313	(15,982)
Other current assets	(18,512)	(8,642)
Accounts payable	(3,355)	37,004
Accrued taxes	132,662	38,963
Other current liabilities	7,981	(66,368)
Change in other long-term assets	(9,478)	(54,872)
Change in other long-term liabilities	(216,308)	(27,521)
Net cash flow provided by operating activities	770,831	830,173
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(971,052)	(857,883)
Contributions in aid of construction	41,457	34,121
Allowance for borrowed funds used during construction	(13,488)	(14,645)
Proceeds from nuclear decommissioning trust sales and other special use funds	607,885	520,996
Investment in nuclear decommissioning trust and other special use funds	(624,249)	(523,573)
Other	(1,260)	(3,563)
Net cash flow used for investing activities	(960,707)	(844,547)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of long-term debt	986,872	794,981
Short-term borrowing and payments — net	0	2,900
Short-term debt borrowings	540,000	0
Short-term debt repayments	(540,000)	0
Repayment of long-term debt	(350,000)	(500,000)
Dividends paid on common stock	(264,000)	(248,300)
Distributions to noncontrolling interests	(11,372)	(11,372)
Net cash flow provided by financing activities	361,500	38,209
NET INCREASE IN CASH AND CASH EQUIVALENTS	171,624	23,835
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	10,169	5,707
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 181,793	$ 29,542