Regulatory Matters Regulatory Matters - Deferred Fuel and Purchased Power Regulatory Asset (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in regulatory asset
Deferred fuel and purchased power	$ (60,303)	$ 14,997	$ (26,927)
Deferred fuel and purchased power amortization	38,152	1,617	40,757
ARIZONA PUBLIC SERVICE COMPANY
Change in regulatory asset
Deferred fuel and purchased power	(60,303)	14,997	(26,927)
Deferred fuel and purchased power amortization	38,152	1,617	40,757
ACC | ARIZONA PUBLIC SERVICE COMPANY | Power Supply Adjustor (PSA) | Cost Recovery Mechanisms
Change in regulatory asset
Beginning balance	(9,688)	6,926
Deferred fuel and purchased power	60,303	(14,997)
Deferred fuel and purchased power amortization	(38,150)	(1,617)
Ending balance	$ 12,465	$ (9,688)	$ 6,926