Commitments and Contingencies - Superfund-Related Matters and Southwest Power Outage (Details) - ARIZONA PUBLIC SERVICE COMPANY $ in Millions			12 Months Ended
	Aug. 06, 2013 Defendant	Sep. 08, 2011 kV Customer	Dec. 31, 2016 USD ($)
Superfund
Costs related to investigation and study under Superfund site | $			$ 2
Southwest Power Outage
Power outage capacity of transmission line that tripped out of service | kV		500
Period, after the transmission line went off-line, over which generation and transmission resources for the Yuma area were lost		10 minutes
Number of customers losing service in Yuma area | Customer		69,700
Contaminated groundwater wells
Superfund
Number of defendants against whom Roosevelt Irrigation District ("RID") filed lawsuit | Defendant	24