Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax [Line Items]
Tax positions, that if recognized, would decrease our effective tax rate	$ 19,504	$ 16,373	$ 11,313
Unrecognized tax benefit interest expense/(benefit) recognized	(780)	577	529
Unrecognized tax benefit interest accrued	1,130	1,910	1,333
ARIZONA PUBLIC SERVICE COMPANY
Income Tax [Line Items]
Tax positions, that if recognized, would decrease our effective tax rate	19,504	16,373	11,313
Unrecognized tax benefit interest expense/(benefit) recognized	(780)	577	529
Unrecognized tax benefit interest accrued	$ 1,130	$ 1,910	$ 1,333