Regulatory Matters (Details) (USD $)	9 Months Ended		0 Months Ended	9 Months Ended		1 Months Ended						3 Months Ended	1 Months Ended					1 Months Ended	9 Months Ended			1 Months Ended					1 Months Ended		6 Months Ended		1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Oct. 02, 2012 ARIZONA PUBLIC SERVICE COMPANY	Sep. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY	Sep. 30, 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	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. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC Cost Recovery Mechanisms	Jun. 02, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 DSMAC Cost Recovery Mechanisms	Jun. 03, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 DSMAC Cost Recovery Mechanisms	Feb. 29, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms USDPerkWh	Sep. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Sep. 30, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Jun. 29, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES MW	Jun. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES Maximum	Jun. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES Minimum	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	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 item	Jun. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY FERC Transmission Rates and Transmission Cost Adjustor Cost Recovery Mechanisms	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%
Settlement Agreement
Net change in base rates																								0
Non-fuel base rate increase																								116,300,000
Fuel-related base rate decrease																								153,100,000
Current base fuel rate (in dollars per kWh)																											0.03757
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%
Percentage of debt in capital structure																										46.10%
Percentage of common equity in capital structure																										53.90%
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																								9
Period to process the subsequent rate cases																								12 months
ACC staff sufficiency findings, general period of time																								30 days
Approved Order
Number of other parties to the settlement agreement																														21
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													102,400,000	92,800,000
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
Capacity from community solar program (in MW)																					25
Period covered by cost recovery program												2 years
Period over which program costs will be amortized												3 years
Percentage of cumulative energy savings for prior year																3.00%
Percentage of annual energy savings to meet energy efficiency goal for 2011																2.75%
Period of energy savings goal															2 years
Percentage of cumulative energy savings for current year																	5.00%
Costs already being recovered in general rates													10,000,000
Demand-side management adjustor charge (DSMAC)														72,000,000
Increase in annual wholesale transmission rates																															16,000,000	44,000,000
Revenue increase related to transmission services used for APS's retail customers																															18,000,000	38,000,000
Revenue reduction related to transmission services used for wholesale customers																															2,000,000
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	51,533,000	30,965,000		51,533,000	30,965,000														(52,000,000)	(31,000,000)
Amounts credited to customers	(91,894,000)	(121,018,000)		(91,894,000)	(121,018,000)														92,000,000	121,000,000
Ending balance																			68,000,000	32,000,000
PSA rate (in dollars per kWh)																		(0.0042)
PSA rate for prior year (in dollars per kWh)																		(0.0057)
Deferred contract termination charges to be amortized over a future period related to proposed acquisition of Southern California Edison			$ 40,000,000
Amortization period				29 years