Nuclear Decommissioning Trusts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nuclear decommissioning trust fund assets
Fair Value	$ 735,196	$ 713,866
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Proceeds from the sale of securities	478,813	356,195	$ 446,025
Fair value of fixed income securities, summarized by contractual maturities
Total	735,196	713,866
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	735,196	713,866
Unrealized Gains	169,053	176,534
Unrealized Losses	(2,760)	(1,088)
Net payables for securities purchases	(335)	(7,245)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	5,189	4,725	5,459
Realized losses	(6,225)	(4,525)	(6,706)
Proceeds from the sale of securities	478,813	356,195	$ 446,025
Fair value of fixed income securities, summarized by contractual maturities
Total	735,196	713,866
ARIZONA PUBLIC SERVICE COMPANY | Equity Securities
Nuclear decommissioning trust fund assets
Fair Value	314,957	309,620
Unrealized Gains	157,098	159,274
Unrealized Losses	(115)	(15)
Fair value of fixed income securities, summarized by contractual maturities
Total	314,957	309,620
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities
Nuclear decommissioning trust fund assets
Fair Value	420,574	411,491
Unrealized Gains	11,955	17,260
Unrealized Losses	(2,645)	(1,073)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	14,001
1 year - 5 years	117,356
5 years - 10 years	114,769
Greater than 10 years	174,448
Total	$ 420,574	$ 411,491