Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal									$ (13,551)	$ 18,375	$ 11,624
State									3,195	3,342	3,052
Total current									(10,356)	21,717	14,676
Deferred:
Federal									(14,982)	94,721	223,729
State									9,565	17,464	19,867
Total deferred									(5,417)	112,185	243,596
Income tax expense/(benefit)	$ (88,537)	$ 53,266	$ 17,080	$ 2,418	$ 6,795	$ 84,333	$ 44,039	$ (1,265)	(15,773)	133,902	258,272
ARIZONA PUBLIC SERVICE COMPANY
Current:
Federal									(54,697)	88,180	21,512
State									695	1,877	2,778
Total current									(54,002)	90,057	24,290
Deferred:
Federal									29,321	32,436	221,078
State									15,109	22,321	23,800
Total deferred									44,430	54,757	244,878
Income tax expense/(benefit)									$ (9,572)	$ 144,814	$ 269,168