Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended		1 Months Ended			1 Months Ended		12 Months Ended
	Dec. 31, 2011 Climate Change Lawsuit oilcompany powercompany	Dec. 31, 2011 Lawsuit complaint	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY minute kV MW customer	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY creditfacility	Sep. 08, 2011 ARIZONA PUBLIC SERVICE COMPANY	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY United States customer	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY Northern Mexico customer	Dec. 31, 2011 Coal take-or-pay commitments ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2010 Coal take-or-pay commitments ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2009 Coal take-or-pay commitments ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 Renewable energy credits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 Coal Mine Reclamation Obligations ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2010 Coal Mine Reclamation Obligations ARIZONA PUBLIC SERVICE COMPANY
Fuel and Purchased Power Commitments and Purchase Obligations
Actual purchases under commitment obligations								$ 68	$ 66	$ 93
Contractual Obligations
2012				580				79			58
2013				528				82			32
2014				556				86			33
2015				535				88			32
2016				503				58			32
Thereafter				6,800				148			388
Total commitments								541				118	117
Total net present value of commitments								401
Climate Change Lawsuit
Number of oil companies	9
Number of power companies	14
Number of consumer class action complaints filed		2
Southwest Power Outage
Capacity of transmission line that tripped out of service (in kV)			500
Period, after the transmission line went off-line, over which generation and transmission resources for the Yuma area were lost (in minutes)			10
Number of customers losing service in Yuma area			69,700
Capacity of firm load that were reported to have been affected due to outages affecting portions of southern Arizona, southern California and northern Mexico (in MW)			7,900
Number of customers that were reported to have been affected due to outages			2,800,000			1,600,000	1,200,000
Maximum possible fine per violation per day that the violation is found to have been in existence					1
Financial Assurances
Outstanding letters of credit to support existing pollution control bonds				44
Letters of credit to support certain equity lessors in the Palo Verde sale leaseback transactions				52
Outstanding letters of credit to support natural gas tolling contract obligations				$ 30
Number of letters of credit issued				2