Regulatory Matters - Four Corners, Cholla and Navajo Plant (Details) - ARIZONA PUBLIC SERVICE COMPANY - USD ($) $ in Millions		1 Months Ended		3 Months Ended
	Dec. 30, 2013	Sep. 30, 2018	Apr. 30, 2018	Jun. 30, 2016	Dec. 31, 2019	Dec. 31, 2015
Retired power plant costs
Acquisition
Regulatory asset, net book value					$ 73.0
Navajo Plant
Acquisition
Regulatory asset, net book value					$ 82.0
SCE | Four Corners
Acquisition
Regulatory assets						$ 12.0
Regulatory assets, write of amount				$ 12.0
Four Corners Units 4 and 5 | SCE
Acquisition
Transmission termination agreement net receipt due to negotiation of alternate arrangement	$ 40.0
Settlement agreement, ACC approved rate adjustment, annualized customer impact		$ 58.5	$ 67.5