Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended		12 Months Ended
	Feb. 29, 2008 Climate Change Lawsuit item	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY kV MW item	Dec. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY item	Sep. 08, 2011 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2012 Coal take-or-pay commitments ARIZONA PUBLIC SERVICE COMPANY	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, 2012 Renewable energy credits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2012 Coal Mine Reclamation Obligations ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 Coal Mine Reclamation Obligations ARIZONA PUBLIC SERVICE COMPANY
Contractual Obligations
2013			$ 585		$ 90			$ 51	$ 1
2014			589		93			40	25
2015			556		96			41	49
2016			522		63			40	25
2017			447		27			40	2
Thereafter			6,600		121			491	17
Total commitments					490				119	118
Total net present value of commitments					375
Actual purchases under commitment obligations					196	191	156
Superfund
Number of oil companies	9
Number of power companies	14
Costs related to investigation and study under Superfund site			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		10 minutes
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		2,700,000
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 variable interest rate pollution control bonds			76
Number of letters of credit expiring in 2015			1
Number of letters of credit expiring in 2016			2
Letters of credit to support certain equity lessors in the Palo Verde sale leaseback transactions			42
Outstanding letters of credit to support natural gas tolling contract obligations			$ 65