Commitments and Contingencies - Superfund-Related Matters and Southwest Power Outage (Details) - ARIZONA PUBLIC SERVICE COMPANY - Contaminated groundwater wells $ in Millions				12 Months Ended
	Apr. 05, 2018 plaintiff Defendant	Dec. 16, 2016 plaintiff	Aug. 06, 2013 Defendant	Dec. 31, 2019 USD ($)
Commitments and Contingencies [Line Items]
Costs related to investigation and study under Superfund site | $				$ 2
Number of defendants against whom Roosevelt Irrigation District ("RID") filed lawsuit | Defendant	28		24
Number of plaintiffs		2
Settled Litigation
Commitments and Contingencies [Line Items]
Number of plaintiffs	2