Nuclear Decommissioning Trust (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Nuclear decommissioning trust fund assets
Fair Value	$ 513,733,000	$ 469,886,000
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Proceeds from the sale of securities	497,780,000	560,469,000	441,242,000
Fair value of fixed income securities, summarized by contractual maturities
Total	513,733,000	469,886,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	513,733,000	469,886,000
Unrealized Gains	67,000,000	55,000,000
Unrealized Losses	(2,000,000)	(3,000,000)
Net payables for securities purchases	(1,000,000)	(10,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	8,000,000	17,000,000	10,000,000
Realized losses	(5,000,000)	(4,000,000)	(7,000,000)
Proceeds from the sale of securities	497,780,000	560,469,000	441,242,000
Fair value of fixed income securities, summarized by contractual maturities
Total	513,733,000	469,886,000
ARIZONA PUBLIC SERVICE COMPANY | Equity securities
Nuclear decommissioning trust fund assets
Fair Value	175,000,000	168,000,000
Unrealized Gains	44,000,000	43,000,000
Unrealized Losses	(1,000,000)	(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Total	175,000,000	168,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	340,000,000	312,000,000
Unrealized Gains	23,000,000	12,000,000
Unrealized Losses	(1,000,000)	(2,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	13,000,000
1 year - 5 years	83,000,000
5 years - 10 years	114,000,000
Greater than 10 years	130,000,000
Total	$ 340,000,000	$ 312,000,000