Long-Term Debt and Liquidity Matters (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Pinnacle West	Dec. 31, 2012 Pinnacle West	Sep. 30, 2013 APS	Dec. 31, 2012 APS	Sep. 30, 2013 APS ACC	Sep. 30, 2013 APS ACC Minimum	Sep. 30, 2013 Long term debt APS item	Sep. 30, 2013 Revolving credit facility maturing in 2016 Pinnacle West	Sep. 30, 2013 Revolving credit facility maturing in 2016 APS	Apr. 09, 2013 Revolving credit facility maturing in 2015 APS	Sep. 30, 2013 Revolving credit facility maturing in 2018 APS	Apr. 09, 2013 Revolving credit facility maturing in 2018 APS	Mar. 22, 2013 4.50% unsecured senior notes that mature on April 1, 2042 APS	May 01, 2013 Pollution Control Revenue Refunding Bonds, 2009 Series C APS	Jul. 12, 2013 Pollution Control Revenue Refunding Bonds, 1994 Series A APS	Oct. 11, 2013 Pollution Control Revenue Refunding Bonds, 1994 Series C APS Subsequent event
Long-Term Debt and Liquidity Matters
Current borrowing capacity on credit facility									$ 1,000,000,000	$ 200,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000
Maximum commercial paper support available under credit facility									250,000,000	200,000,000
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders										300,000,000	700,000,000		700,000,000
Outstanding borrowings										0	0		0
Outstanding letters of credit										0	0		0
Commercial paper borrowings outstanding									0	0
Notes issued															100,000,000
Interest rate (as a percent)															4.50%	1.75%
Long-term debt redemption																32,000,000	33,000,000	32,000,000
Number of line of credit facilities									2
Estimated fair value of long-term debt, including current maturities
Carrying Amount	3,387,000,000	3,322,000,000	125,000,000	125,000,000	3,262,000,000	3,197,000,000
Fair Value	3,663,000,000	3,875,000,000	125,000,000	125,000,000	3,538,000,000	3,750,000,000
Debt Provisions
Required common equity ratio ordered by ACC (as a percent)								40.00%
Total shareholder equity	4,275,804,000	3,972,806,000			4,392,797,000	4,093,000,000	4,400,000,000
Total capitalization							7,600,000,000
Dividend restrictions, shareholder equity required								$ 3,000,000,000