Nuclear Decommissioning Trust (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Nuclear decommissioning trust fund assets
Fair Value	$ 544,933,000		$ 544,933,000		$ 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			211,138,000	299,600,000
Fair value of fixed income securities, summarized by contractual maturities
Total	544,933,000		544,933,000		513,733,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	544,933,000		544,933,000		513,733,000
Unrealized Gains	82,000,000		82,000,000		67,000,000
Unrealized Losses	(1,000,000)		(1,000,000)		(2,000,000)
Net payables for securities purchases	(6,000,000)		(6,000,000)		(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	2,000,000	4,000,000	3,000,000
Realized losses	(1,000,000)	(1,000,000)	(2,000,000)	(3,000,000)
Proceeds from the sale of securities	119,000,000	110,000,000	211,138,000	299,600,000
Fair value of fixed income securities, summarized by contractual maturities
Total	544,933,000		544,933,000		513,733,000
ARIZONA PUBLIC SERVICE COMPANY | Equity securities
Nuclear decommissioning trust fund assets
Fair Value	192,000,000		192,000,000		175,000,000
Unrealized Gains	58,000,000		58,000,000		44,000,000
Unrealized Losses	(1,000,000)		(1,000,000)		(1,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Total	192,000,000		192,000,000		175,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	359,000,000		359,000,000		340,000,000
Unrealized Gains	24,000,000		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	24,000,000		24,000,000
1 year - 5 years	82,000,000		82,000,000
5 years - 10 years	103,000,000		103,000,000
Greater than 10 years	150,000,000		150,000,000
Total	$ 359,000,000		$ 359,000,000		$ 340,000,000