Lines of Credit and Short-Term Borrowings (Details) (USD $)					12 Months Ended				12 Months Ended									12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Pinnacle West	Dec. 31, 2011 Pinnacle West Long term debt	Dec. 31, 2010 Pinnacle West Revolving credit facility maturing in 2013	Dec. 31, 2011 Pinnacle West Revolving credit facility maturing in 2013	Nov. 04, 2011 Pinnacle West Revolving credit facility maturing in 2013	Feb. 12, 2010 Pinnacle West Revolving credit facility maturing in 2013	Dec. 31, 2011 Pinnacle West Revolving credit facility maturing in 2016	Nov. 04, 2011 Pinnacle West Revolving credit facility maturing in 2016	Dec. 31, 2011 Pinnacle West Commercial Paper	Dec. 31, 2010 Pinnacle West Commercial Paper	Feb. 12, 2010 Pinnacle West Revolving credit facility maturing in 2010	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC	Nov. 22, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC	Oct. 30, 2007 ARIZONA PUBLIC SERVICE COMPANY ACC	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY Long term debt	Dec. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2013	Nov. 04, 2011 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2013	Feb. 12, 2010 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2013	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2016	Nov. 04, 2011 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2016	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2015	Feb. 14, 2011 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2015	Dec. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY Line of Credit Maturing in 2011	Feb. 14, 2011 ARIZONA PUBLIC SERVICE COMPANY Line of Credit Maturing in 2011	Feb. 12, 2010 ARIZONA PUBLIC SERVICE COMPANY Revolving credit facility maturing in 2010
Lines of Credit and Short-Term Borrowings
Amount Committed	$ 1,200,000,000	$ 1,189,000,000			$ 200,000,000		$ 200,000,000	$ 200,000,000	$ 200,000,000	$ 200,000,000	$ 200,000,000		$ 283,000,000					$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 489,000,000	$ 489,000,000	$ 377,000,000
Letters of Credit Used		20,000,000																							20,000,000
Short-Term Borrowings		16,600,000	16,600,000									17,000,000
Unused Amount	1,200,000,000	1,152,000,000			183,000,000				200,000,000									500,000,000			500,000,000		500,000,000		469,000,000
Weighted Average Interest Rate (as a percent)												0.84%
Commitment Fees (as a percent)					0.625%				0.275%									0.50%			0.225%		0.25%		0.10%
Maximum commercial paper support available under credit facility				200,000,000													250,000,000
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders						300,000,000															700,000,000		700,000,000
Debt Provisions
Short-term debt authorization as a percentage of APS's capitalization before increase																7.00%
Percentage of APS's capitalization used in calculation of short-term debt authorization														7.00%
Required amount to be used in purchases of natural gas and power which is used in calculation of short-term debt authorization														500,000,000
Long-term debt authorization before increase																3,200,000,000
Long-term debt authorization														4,200,000,000
Long-term debt authorization requested in a financing application															$ 5,500,000,000