Nuclear Decommissioning Trusts (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Nuclear decommissioning trust fund assets
Fair Value	$ 570,625,000	$ 513,733,000
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Proceeds from the sale of securities	417,603,000	497,780,000	560,469,000
Fair value of fixed income securities, summarized by contractual maturities
Total	570,625,000	513,733,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	570,625,000	513,733,000
Unrealized Gains	91,000,000	67,000,000
Unrealized Losses		(2,000,000)
Net payables for securities purchases	(4,000,000)	(1,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	7,000,000	8,000,000	17,000,000
Realized losses	(4,000,000)	(5,000,000)	(4,000,000)
Proceeds from the sale of securities	417,603,000	497,780,000	560,469,000
Fair value of fixed income securities, summarized by contractual maturities
Total	570,625,000	513,733,000
ARIZONA PUBLIC SERVICE COMPANY | Equity Securities
Nuclear decommissioning trust fund assets
Fair Value	204,000,000	175,000,000
Unrealized Gains	67,000,000	44,000,000
Unrealized Losses		(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Total	204,000,000	175,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	371,000,000	340,000,000
Unrealized Gains	24,000,000	23,000,000
Unrealized Losses		(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	14,000,000
1 year - 5 years	97,000,000
5 years - 10 years	109,000,000
Greater than 10 years	151,000,000
Total	$ 371,000,000	$ 340,000,000