Regulatory Matters - Four Corners, Cholla and Navajo Plant (Details) - ARIZONA PUBLIC SERVICE COMPANY - USD ($) $ in Millions	1 Months Ended
	Sep. 30, 2018	Apr. 30, 2018	Dec. 31, 2020
Retired power plant costs
Acquisition
Regulatory asset, net book value			$ 57.0
Navajo plant
Acquisition
Regulatory asset, net book value			72.0
Navajo plant, coal reclamation regulatory asset
Acquisition
Regulatory asset, net book value			$ 18.0
Four Corners Units 4 and 5 | SCE
Acquisition
Settlement agreement, ACC approved rate adjustment, annualized customer impact	$ 58.5	$ 67.5