Nuclear Decommissioning Trust (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Nuclear decommissioning trust fund assets
Fair Value	$ 541,989,000		$ 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	92,047,000	189,318,000
Fair value of fixed income securities, summarized by contractual maturities
Total	541,989,000		513,733,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	541,989,000		513,733,000
Unrealized Gains	85,000,000		67,000,000
Unrealized Losses	(1,000,000)		(2,000,000)
Net receivables from securities sales	(1,000,000)
Net payables for securities purchases			(1,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	2,000,000	1,000,000
Realized losses	(1,000,000)	(2,000,000)
Proceeds from the sale of securities	92,047,000	189,318,000
Fair value of fixed income securities, summarized by contractual maturities
Total	541,989,000		513,733,000
ARIZONA PUBLIC SERVICE COMPANY | Equity securities
Nuclear decommissioning trust fund assets
Fair Value	196,000,000		175,000,000
Unrealized Gains	64,000,000		44,000,000
Unrealized Losses			(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Total	196,000,000		175,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	347,000,000		340,000,000
Unrealized Gains	21,000,000		23,000,000
Unrealized Losses	(1,000,000)		(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	19,000,000
1 year - 5 years	85,000,000
5 years - 10 years	107,000,000
Greater than 10 years	136,000,000
Total	$ 347,000,000		$ 340,000,000