Income Taxes - Components of Deferred Income Tax Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
DEFERRED TAX ASSETS
Risk management activities	$ 31,411	$ 8,826
Regulatory liabilities:
Excess deferred income taxes — Tax Cuts and Jobs Act	283,161	295,014
Asset retirement obligation and removal costs	113,312	107,104
Unamortized investment tax credits	68,521	48,035
Other postretirement benefits	56,070	66,893
Other	39,857	62,915
Operating lease liabilities	316,067	184,030
Pension liabilities	33,294	33,674
Coal reclamation liabilities	45,505	44,312
Renewable energy incentives	17,261	19,948
Credit and loss carryforwards	43,940	37,647
Other	77,865	72,605
Total deferred tax assets	1,126,264	981,003
DEFERRED TAX LIABILITIES
Plant-related	(2,572,495)	(2,518,164)
Risk management activities	(1,682)	(32,648)
Pension and other postretirement assets	(78,853)	(96,845)
Other special use funds	(56,550)	(57,572)
Operating lease right-of-use assets	(316,067)	(184,030)
Regulatory assets:
Allowance for equity funds used during construction	(46,754)	(44,405)
Deferred fuel and purchased power	(149,078)	(114,232)
Pension benefits	(172,239)	(157,629)
Retired power plant costs	(20,659)	(24,397)
Other	(92,260)	(103,023)
Other	(36,107)	(32,479)
Total deferred tax liabilities	(3,542,744)	(3,365,424)
Deferred income taxes — net	(2,416,480)	(2,384,421)
Arizona Public Service Company
DEFERRED TAX ASSETS
Risk management activities	31,411	8,826
Regulatory liabilities:
Excess deferred income taxes — Tax Cuts and Jobs Act	283,161	295,014
Asset retirement obligation and removal costs	113,312	107,104
Unamortized investment tax credits	68,521	48,035
Other postretirement benefits	56,070	66,893
Other	39,857	62,915
Operating lease liabilities	315,670	182,663
Pension liabilities	29,918	30,436
Coal reclamation liabilities	45,505	44,312
Renewable energy incentives	17,261	19,948
Credit and loss carryforwards	3,031	13,654
Other	77,865	72,605
Total deferred tax assets	1,081,582	952,405
DEFERRED TAX LIABILITIES
Plant-related	(2,572,495)	(2,518,164)
Risk management activities	(1,682)	(32,648)
Pension and other postretirement assets	(78,297)	(96,196)
Other special use funds	(56,550)	(57,572)
Operating lease right-of-use assets	(315,670)	(182,663)
Regulatory assets:
Allowance for equity funds used during construction	(46,754)	(44,405)
Deferred fuel and purchased power	(149,078)	(114,232)
Pension benefits	(172,239)	(157,629)
Retired power plant costs	(20,659)	(24,397)
Other	(92,260)	(103,023)
Other	(7,595)	(7,123)
Total deferred tax liabilities	(3,513,279)	(3,338,052)
Deferred income taxes — net	$ (2,431,697)	$ (2,385,647)