Regulatory Matters (Details) (USD $)	3 Months Ended				1 Months Ended						3 Months Ended	1 Months Ended	12 Months Ended			1 Months Ended			1 Months Ended	3 Months Ended		1 Months Ended				1 Months Ended		6 Months Ended		1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY	Mar. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Maximum USDPerWatt	Jul. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Maximum	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Minimum USDPerWatt	Jul. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Minimum	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Cost Recovery Mechanisms USDPerWatt	Dec. 14, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Cost Recovery Mechanisms MW	Mar. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2010 DSMAC Cost Recovery Mechanisms Y	Feb. 28, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC Cost Recovery Mechanisms	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC Cost Recovery Mechanisms	Feb. 17, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC Cost Recovery Mechanisms	Jun. 02, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC Cost Recovery Mechanisms	Jun. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC Cost Recovery Mechanisms	Apr. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC Cost Recovery Mechanisms	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC Cost Recovery Mechanisms	Feb. 28, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms USDPerkWh	Mar. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Mar. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Jan. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Filing with the Arizona Corporation Commission	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Filing with the Arizona Corporation Commission	Jan. 06, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Filing with the Arizona Corporation Commission	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Filing with the Arizona Corporation Commission	Jan. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Current	Dec. 31, 2009 ARIZONA PUBLIC SERVICE COMPANY ACC 2008 General retail rate case	Jun. 30, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2008 General retail rate case	Dec. 30, 2009 ARIZONA PUBLIC SERVICE COMPANY ACC 2008 General retail rate case party	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY FERC Transmission Rates and Transmission Cost Adjustor Cost Recovery Mechanisms
Regulatory Matters
Net retail rate increase																							$ 95,500,000
Approximate percentage of increase in the average retail customer bill																							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																									46.10%
Percentage of common stock equity in capital structure																									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			0.03757
Current sharing provision of fuel and purchased power costs																							90/10
Settlement Agreement
Net change in base rates																						0
Non-fuel base rate increase																						116,300,000
Fuel-related base rate decrease																						153,100,000
Estimated amount of transfer of cost recovery for certain renewable energy projects from the RES surcharge to base rates																						36,800,000
Authorized return on common equity (as a percent)																								10.00%					11.00%
Percentage of debt in capital structure																								46.10%					46.20%
Percentage of common equity in capital structure																								53.90%					53.80%
Deferral of property taxes in 2012, if Arizona property tax rates increase (as a percent)																								25.00%
Deferral of property taxes in 2013, if Arizona property tax rates increase (as a percent)																								50.00%
Deferral of property taxes for 2014 and subsequent years, if Arizona property tax rates increase (as a percent)																								75.00%
Deferral of property taxes in all years, if Arizona property tax rates decrease (as a percent)																								100.00%
Annual cost recovery due to modifications to the Environmental Improvement Surcharge																						5,000,000
Elimination of the current sharing provision of fuel and purchased power costs																						90/10
Approved Order
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
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																												253,000,000
Funding request						152,000,000		129,000,000					79,000,000
Funding approval as per budget authorized									110,000,000
Additional capacity from APS-owned AZ Sun projects (in MW)										100
Total capacity from APS-owned AZ Sun projects (in MW)										200
Second additional solar capacity for which revenue requirements were authorized to be recovered										100
Costs associated with program to be recovered through base rates or other mechanisms or next retail rate base (in MW)										100
Additional capacity from APS-owned facilities on schools and government facilities (in MW)										6.25
Initial upfront incentive per watt of solar capacity (in dollars per watt)									0.75
Amount for residential incentives for next fiscal year (in dollars per watt)					0.20		0.10
Additional capacity of renewable generation to be described later and installed in 2014 and 2015 (in MW)										25
Period covered by cost recovery program (in years)											2
Period over which program costs will be amortized (in years)											3
Percentage of energy savings for prior year																		1.75%
Percentage of annual energy savings to meet energy efficiency goal for 2011															1.25%			1.50%
Amount of approved budget														80,000,000
Costs already being recovered in general rates												10,000,000				10,000,000
Demand-side management adjustor charge (DSMAC)												75,000,000					72,000,000
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																				28,000,000	(58,000,000)
Deferred fuel and purchased power costs-current period	46,754,000	49,947,000	46,754,000	49,947,000																(47,000,000)	(50,000,000)
Amounts refunded through revenues	(24,514,000)	(31,238,000)	(24,514,000)	(31,238,000)																24,000,000	31,000,000
Ending balance																				$ (5,000,000)	$ (77,000,000)
PSA rate (in dollars per kWh)																			(0.0042)
PSA rate for prior year (in dollars per kWh)																			(0.0057)