Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended			3 Months Ended
	Feb. 28, 2011 Y	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY M	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY
Income Taxes
Income tax receivables		$ 69,069	$ 68,633	$ 69,464	$ 69,028
Period over which the cash refunds are not expected to be received (in months)				12
Phase-in period of corporate income tax rate reductions beginning in 2014 (in years)	4