Stock-Based Compensation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010	Dec. 31, 2009
Additional disclosures
Total unrecognized compensation cost related to nonvested share-based compensation arrangements granted	$ 20,500,000
Expected weighted-average period of recognition of unrecognized compensation cost (in years)	2.2
Total fair value of shares vested	14,400,000	11,000,000	10,000,000
Compensation cost that has been charged against income	23,000,000	15,000,000	5,000,000
Total income tax benefit recognized	9,000,000	6,000,000	2,000,000
ARIZONA PUBLIC SERVICE COMPANY
Additional disclosures
Compensation cost that has been charged against income	22,000,000	15,000,000	4,000,000
Stock Options
Stock option activity under prior equity incentive plans
Outstanding at the beginning of the period (in shares)	82,224
Exercised (in shares)	44,766
Forfeited or expired (in shares)	14,500
Outstanding at the end of the period (in shares)	22,958	82,224
Exercisable at the end of the period (in shares)	22,958
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 39.37
Exercised (in dollars per share)	$ 40.70
Forfeited or expired (in dollars per share)	$ 42.55
Outstanding at the end of the period (in dollars per share)	$ 34.75	$ 39.37
Exercisable at the end of the period (in dollars per share)	$ 34.75
Weighted-Average Remaining Contractual Term (in months)
Outstanding at the end of the period (in months)	11
Exercisable at the end of the period (in months)	11
Aggregate Intrinsic Value
Outstanding at the end of the period	308,000
Exercisable at the end of the period	308,000
Additional disclosures
Cash received from options exercised	$ 1,800,000	$ 4,600,000	$ 3,000,000
Stock Options | Maximum
Stock-Based Compensation
Term of outstanding options (in years)	10Y