Commitments and Contingencies (Details 2) (ARIZONA PUBLIC SERVICE COMPANY, USD $) In Millions, unless otherwise specified	1 Months Ended	9 Months Ended		0 Months Ended
	Sep. 30, 2011 item kV MW	Sep. 30, 2013 item	Sep. 08, 2011	Aug. 06, 2013 Contaminated groundwater wells item
Contractual Obligations
Decrease in contractual obligations for fuel and purchased power commitments		$ 300
2013		108
2014		576
2015		549
2016		516
2017		441
Thereafter		6,399
Total commitments		8,589
Superfund-Related Matters
Costs related to investigation and study under Superfund site		2
Number of defendants against whom Roosevelt Irrigation District ("RID") filed lawsuit				24
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		32
Outstanding letters of credit to support natural gas tolling contract obligations		$ 60