Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Tax positions, that if recognized, would decrease our effective tax rate	$ 11,313	$ 9,523	$ 11,207
Unrecognized tax benefit interest expense/(benefit) recognized	529	(161)	752
Unrecognized tax benefit interest accrued	1,333	804	965
ARIZONA PUBLIC SERVICE COMPANY
Income Tax [Line Items]
Tax positions, that if recognized, would decrease our effective tax rate	11,313	9,523	11,207
Unrecognized tax benefit interest expense/(benefit) recognized	529	(161)	752
Unrecognized tax benefit interest accrued	$ 1,333	$ 804	$ 965