Regulatory Matters (Details) (USD $)	12 Months Ended			1 Months Ended	6 Months Ended	12 Months Ended			1 Months Ended		1 Months Ended						12 Months Ended			1 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended				1 Months Ended			6 Months Ended		1 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY	Jun. 30, 2010 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2009 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES USDPerWatt	Dec. 14, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES MW	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	Mar. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2010 DSMAC Y	Feb. 28, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC	Feb. 17, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC	Jun. 02, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 DSMAC	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC	Feb. 28, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) USDPerkWh	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) USDPerkWh	Dec. 31, 2010 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA)	Jan. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case	Jun. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case USDPerkWh	Jan. 06, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case	Jan. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Proposed USDPerkWh	Jan. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2011 General retail rate case Current USDPerkWh	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
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
Approved base fuel rate (in dollars per kWh)																													0.03207
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 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
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	252,833,000																											253,000,000
Funding request												152,000,000		129,000,000			79,000,000			90,000,000
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 of solar capacity for residential incentives for next fiscal year											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				85,000,000
Deferral of the difference between retail fuel and purchased power costs and the Base Fuel Rate (as a percent)																							90.00%
Absorption of the retail fuel and purchased power costs above the Base Fuel Rate (as a percent)																							10.00%
Retention of the benefit from the retail fuel and purchased power costs that are below the Base Fuel Rate (as a percent)																							10.00%
Maximum increase or decrease in PSA rate without permission of the ACC (in dollars per kWh)																							0.004
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	69,166,000	93,631,000	(51,742,000)			69,166,000	93,631,000	(51,742,000)															(69,000,000)	(93,000,000)
Amounts refunded through revenues	(155,157,000)	(122,481,000)	147,018,000			(155,157,000)	(122,481,000)	147,018,000															155,000,000	122,000,000
Ending balance																							$ 28,000,000	$ (58,000,000)
PSA rate (in dollars per kWh)																						(0.0042)
PSA rate for prior year (in dollars per kWh)																						(0.0057)