Asset Retirement Obligations - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Asset Retirement Obligations
Palo Verde sale leaseback property plant and equipment, net of accumulated depreciation	$ 17,606,771	$ 16,854,354
APS
Asset Retirement Obligations
Palo Verde sale leaseback property plant and equipment, net of accumulated depreciation	17,606,378	$ 16,800,254
Cholla | APS
Asset Retirement Obligations
Asset retirement obligation, period increase (decrease)	36,000
Four Corners Coal-Fired Power Plant | APS
Asset Retirement Obligations
Asset retirement obligation, period increase (decrease)	(7,000)
Palo Verde | APS
Asset Retirement Obligations
Asset retirement obligation, period increase (decrease)	33,000
Palo Verde sale leaseback property plant and equipment, net of accumulated depreciation	34,000
Regulatory Liability	1,000
Navajo Coal-Fired Power Plant | APS
Asset Retirement Obligations
Asset retirement obligation, period increase (decrease)	$ 8,000