Regulatory Matters (Details) (USD $)	9 Months Ended				1 Months Ended		9 Months Ended		1 Months Ended		6 Months Ended		12 Months Ended			1 Months Ended		1 Months Ended			1 Months Ended						1 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY	Sep. 30, 2010 ARIZONA PUBLIC SERVICE COMPANY	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case USDPerkWh mechanism	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2010 RES y	Mar. 03, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2010 RES mW	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY FERC Transmission Rates and Transmission Cost Adjustor	Dec. 31, 2009 ARIZONA PUBLIC SERVICE COMPANY 2008 General retail rate case	Jun. 30, 2010 ARIZONA PUBLIC SERVICE COMPANY 2008 General retail rate case	Dec. 30, 2009 ARIZONA PUBLIC SERVICE COMPANY 2008 General retail rate case party	Dec. 31, 2009 ARIZONA PUBLIC SERVICE COMPANY 2010 RES	Apr. 02, 2010 ARIZONA PUBLIC SERVICE COMPANY 2010 RES customer mW	Mar. 03, 2010 ARIZONA PUBLIC SERVICE COMPANY 2010 RES mW	Jul. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY 2011 RES	Oct. 13, 2010 ARIZONA PUBLIC SERVICE COMPANY 2011 RES mW	Jul. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY 2012 RES	Oct. 26, 2011 ARIZONA PUBLIC SERVICE COMPANY 2012 RES mW	Jul. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY 2012 RES mW	Mar. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY 2010 DSMAC y	Jul. 31, 2009 ARIZONA PUBLIC SERVICE COMPANY 2010 DSMAC	Feb. 28, 2011 ARIZONA PUBLIC SERVICE COMPANY 2011 DSMAC	Jun. 30, 2010 ARIZONA PUBLIC SERVICE COMPANY 2011 DSMAC	Feb. 17, 2011 ARIZONA PUBLIC SERVICE COMPANY 2011 DSMAC	Jun. 02, 2010 ARIZONA PUBLIC SERVICE COMPANY 2011 DSMAC	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY 2012 DSMAC	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY 2012 DSMAC	Feb. 28, 2011 Power Supply Adjustor (PSA)	Sep. 30, 2011 Power Supply Adjustor (PSA)	Sep. 30, 2010 Power Supply Adjustor (PSA)
Regulatory Matters
Net retail rate increase					$ 95,500,000
Approximate percentage of increase in the average retail customer bill (as a percent)					6.60%
Non-fuel base rate increase					194,100,000
Reclassification of revenues to base rates					44,900,000
Base rate decrease					143,500,000
Rate base					5,700,000,000
Proposed capital structure and costs of capital
Percentage of long-term debt in capital structure (as a percent)						46.10%
Percentage of common stock equity in capital structure (as a percent)						53.90%
Cost of capital, long-term debt (as a percent)						6.38%
Cost of capital, common stock equity (as a percent)						11.00%
Weighted-average cost of capital (as a percent)						8.87%
Proposed base fuel rate (in dollars per kWh)					0.03242
Current base fuel rate (in dollars per kWh)					0.03757
Current sharing provision of fuel and purchased power costs					90/10
Number of new recovery mechanisms that would adjust electricity rates					2
Approved Settlement
Number of other parties to the settlement agreement												21
Net retail rate increase										207,500,000
Base rate increase										344,700,000
Reclassification of fuel and purchased power revenues from the then-existing PSA to base rates										137,200,000
Authorized return on common equity (as a percent)												11.00%
Percentage of debt in capital structure (as a percent)												46.20%
Percentage of common equity in capital structure (as a percent)												53.80%
Minimum amount of reduction of average annual operational expenses from 2010 through 2014										30,000,000
Authorization and requirements of equity infusions into APS beginning June 1, 2009 through December 31, 2014										700,000,000
Equity infusions into APS				252,833,000							253,000,000
Plan term (in years)							5
Funding request													87,000,000			96,000,000						50,000,000		79,000,000			90,000,000
Funding request, low end of range																		129,000,000
Funding request, high end of range																		152,000,000
Capacity from third-parties entirely through power purchase agreements (PPAs) or through a mix of PPAs and non-residential distributed energy programs (in MW)																				150
Additional capacity from APS-owned AZ Sun projects (in MW)																				100
Capacity associated with APS-owned AZ Sun project to be recovered currently through implementation plan (in MW)																				19
Proposed additional capacity from APS-owned systems on school and government facilities (in MW)																				25
Addition of owned solar resources (in MW)								100						1.5
Maximum future investment planned in solar photovoltaic projects across Arizona															500,000,000
Costs associated with program to be recovered through base rates or other mechanisms (in MW)															50
Costs associated with program to be recovered through next retail rate base (in MW)															50
Number of residential and business customers with solar paneled rooftops														200
Addition of biomass capacity (in MW)																	10
Period covered by cost recovery program (in years)																					2
Period over which program costs will be recovered (in years)																					3
Percentage of energy savings for prior year (as a percent)																												1.75%
Percentage of annual energy savings to meet energy efficiency goal for 2011 (as a percent)																										1.25%		1.50%
Amount of approved budget																									80,000,000
Recommended budget amount																			131,700,000
Recommended additional capacity from APS-owned systems on school and government facilities (in MW)																			15
Costs already being recovered in general rates																							10,000,000				10,000,000
Demand-side management adjustor charge (DSMAC)																							75,000,000				85,000,000
Increase in annual wholesale transmission rates									44,000,000
Revenue increase related to transmission services used for APS's retail customers									38,000,000
Changes in the deferred fuel and purchased power regulatory asset (liability)
Beginning balance																														(58,000,000)	(87,000,000)
Deferred fuel and purchased power costs-current period	30,965,000	50,020,000	30,965,000	50,020,000																										(31,000,000)	(50,000,000)
Amounts refunded through revenues	(121,018,000)	(95,926,000)	(121,018,000)	(95,926,000)																										121,000,000	96,000,000
Ending balance																														$ 32,000,000	$ (41,000,000)
PSA rate (in dollars per kWh)																													(0.0057)
PSA rate for prior year (in dollars per kWh)																													(0.0045)