Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Income Taxes
Long-term income tax receivables	$ 70,828,000	$ 70,389,000
Income Taxes, additional disclosures
Percentage of bonus depreciation for federal income tax purposes	50.00%
Federal general business income tax credit carryforwards whose realization will be delayed on recognition of cash benefit		78,000,000
Palo Verde VIE
Income Taxes
Income tax expense associates with the VIE's	0
ARIZONA PUBLIC SERVICE COMPANY
Income Taxes
Long-term income tax receivables	$ 71,223,000	$ 70,784,000
Period over which the cash refunds are not expected to be received	12 months