Income Taxes (Details) (USD $)	3 Months Ended	9 Months Ended
	Mar. 31, 2011	Sep. 30, 2011 customer y GWh billionbtu	Dec. 31, 2010
Income Taxes
Income tax receivables		$ 68,201,000	$ 65,103,000
Phase-in period of corporate income tax rate reductions beginning in 2014 (in years)		4
Decrease in deferred income tax liabilities	53,000,000
Change in regulatory liabilities	53,000,000
ARIZONA PUBLIC SERVICE COMPANY
Income Taxes
Income tax receivables		68,596,000	65,498,000
Period over which the cash refunds are not expected to be received (in months)		12
Change in regulatory liabilities	$ 12,000,000