Nuclear Decommissioning Trusts (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nuclear decommissioning trust fund assets
Fair Value	$ 713,866,000	$ 642,007,000
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Proceeds from the sale of securities	356,195,000	446,025,000	417,603,000
Fair value of fixed income securities, summarized by contractual maturities
Total	713,866,000	642,007,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	713,866,000	642,007,000
Unrealized Gains	176,000,000	140,000,000
Unrealized Losses	(1,000,000)	(6,000,000)
Net payables for securities purchases	(7,000,000)	(3,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	5,000,000	6,000,000	7,000,000
Realized losses	(5,000,000)	(7,000,000)	(4,000,000)
Proceeds from the sale of securities	356,195,000	446,025,000	417,603,000
Fair value of fixed income securities, summarized by contractual maturities
Total	713,866,000	642,007,000
ARIZONA PUBLIC SERVICE COMPANY | Equity Securities
Nuclear decommissioning trust fund assets
Fair Value	310,000,000	272,000,000
Unrealized Gains	159,000,000	129,000,000
Fair value of fixed income securities, summarized by contractual maturities
Total	310,000,000	272,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities
Nuclear decommissioning trust fund assets
Fair Value	411,000,000	373,000,000
Unrealized Gains	17,000,000	11,000,000
Unrealized Losses	(1,000,000)	(6,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	14,000,000
1 year - 5 years	116,000,000
5 years - 10 years	122,000,000
Greater than 10 years	159,000,000
Total	$ 411,000,000	$ 373,000,000