Nuclear Decommissioning Trusts (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Nuclear decommissioning trust fund assets
Fair Value	$ 612,640,000		$ 612,640,000		$ 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			363,944,000	295,126,000
Fair value of fixed income securities, summarized by contractual maturities
Total	612,640,000		612,640,000		570,625,000
ARIZONA PUBLIC SERVICE COMPANY
Nuclear decommissioning trust fund assets
Fair Value	612,640,000		612,640,000		570,625,000
Unrealized Gains	117,000,000		117,000,000		91,000,000
Unrealized Losses	(5,000,000)		(5,000,000)
Net payables for securities purchases	(3,000,000)		(3,000,000)		(4,000,000)
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	1,000,000	1,000,000	4,000,000	5,000,000
Realized losses	(3,000,000)	(1,000,000)	(5,000,000)	(3,000,000)
Proceeds from the sale of securities	110,000,000	84,000,000	363,944,000	295,126,000
Fair value of fixed income securities, summarized by contractual maturities
Total	612,640,000		612,640,000		570,625,000
ARIZONA PUBLIC SERVICE COMPANY | Equity Securities
Nuclear decommissioning trust fund assets
Fair Value	245,000,000		245,000,000		204,000,000
Unrealized Gains	104,000,000		104,000,000		67,000,000
Fair value of fixed income securities, summarized by contractual maturities
Total	245,000,000		245,000,000		204,000,000
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities.
Nuclear decommissioning trust fund assets
Fair Value	371,000,000		371,000,000		371,000,000
Unrealized Gains	13,000,000		13,000,000		24,000,000
Unrealized Losses	(5,000,000)		(5,000,000)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	12,000,000		12,000,000
1 year - 5 years	106,000,000		106,000,000
5 years - 10 years	104,000,000		104,000,000
Greater than 10 years	149,000,000		149,000,000
Total	$ 371,000,000		$ 371,000,000		$ 371,000,000