Nuclear Decommissioning Trust (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Nuclear decommissioning trust fund assets
Fair Value	$ 596,168,000		$ 570,625,000
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Proceeds from the sale of securities	135,240,000	92,047,000
Fair value of fixed income securities, summarized by contractual maturities
Total	596,168,000		570,625,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	596,168,000		570,625,000
Unrealized Gains	108,000,000		91,000,000
Unrealized Losses	(1,000,000)
Net payables for securities purchases	(9,000,000)		(4,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	2,000,000	2,000,000
Realized losses	(1,000,000)	(1,000,000)
Proceeds from the sale of securities	135,240,000	92,047,000
Fair value of fixed income securities, summarized by contractual maturities
Total	596,168,000		570,625,000
ARIZONA PUBLIC SERVICE COMPANY | Equity Securities
Nuclear decommissioning trust fund assets
Fair Value	226,000,000		204,000,000
Unrealized Gains	87,000,000		67,000,000
Fair value of fixed income securities, summarized by contractual maturities
Total	226,000,000		204,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	379,000,000		371,000,000
Unrealized Gains	21,000,000		24,000,000
Unrealized Losses	(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	17,000,000
1 year - 5 years	105,000,000
5 years - 10 years	100,000,000
Greater than 10 years	157,000,000
Total	$ 379,000,000		$ 371,000,000