Regulatory Matters (Details) (USD $)	3 Months Ended					12 Months Ended	0 Months Ended	3 Months Ended		1 Months Ended		3 Months Ended	1 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, 2013	Mar. 31, 2012	Mar. 31, 2013 Power Supply Adjustor (PSA)	Mar. 31, 2013 ARIZONA PUBLIC SERVICE COMPANY	Mar. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY 2013 DSMAC	Feb. 12, 2013 ARIZONA PUBLIC SERVICE COMPANY Lost Fixed Cost Recovery Mechanism	Mar. 31, 2013 ARIZONA PUBLIC SERVICE COMPANY Lost Fixed Cost Recovery Mechanism	Mar. 31, 2013 ARIZONA PUBLIC SERVICE COMPANY ACC RES	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY ACC 2012 RES Cost Recovery Mechanisms	Jun. 02, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 DSMAC Cost Recovery Mechanisms	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. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES Minimum	Jun. 30, 2012 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES Maximum	Jan. 31, 2013 ARIZONA PUBLIC SERVICE COMPANY ACC 2013 RES Maximum	Feb. 28, 2013 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Mar. 31, 2013 ARIZONA PUBLIC SERVICE COMPANY ACC Power Supply Adjustor (PSA) Cost Recovery Mechanisms	Mar. 31, 2012 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	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 item	Jun. 30, 2012 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 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
Plan term									5 years
Funding request																	97,000,000	107,000,000
Funding approval as per budget authorized										110,000,000
Amount of approved budget																			103,000,000
Amount of approved budget for residential distributed energy up-front incentives																			4,000,000
Amount of approved budget for commercial distributed energy up-front incentives																			100,000
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
Demand-side management adjustor charge (DSMAC)														72,000,000
Costs already being recovered in general rates													10,000,000
Percentage of cumulative energy savings for current year											5.00%
Amount of proposed budget						87,600,000
Amount by which proposed budget exceeds approved budget						5,600,000
Expiration of amortization period of costs and prior year credits						3 years
Change in regulatory asset (liability)
Beginning balance																					73,000,000	28,000,000
Deferred fuel and purchased power costs-current period	(31,194,000)	(46,754,000)		(31,194,000)	(46,754,000)																31,000,000	47,000,000
Amounts (collected from) credited to customers	(1,122,000)	24,514,000		(1,122,000)	24,514,000																1,000,000	(24,000,000)
Ending balance																					41,000,000	5,000,000
PSA rate (in dollars per kWh)																				0.0013
PSA rate for prior year (in dollars per kWh)																				(0.0042)
Increase in PSA charge (in dollars per kWh)			0.0055
Forward component of increase in PSA (in dollars per kWh)			(0.0010)
Historical component of increase in PSA (in dollars per kWh)			0.0023
Maximum increase or decrease in PSA charge without permission of the ACC (in dollars per kWh)			0.004
Increase in annual wholesale transmission rates																														16,000,000
Revenue increase related to transmission services used for APS's retail customers																														18,000,000
Revenue reduction related to transmission services used for wholesale customers																														2,000,000
Deferred contract termination charges to be amortized over a future period related to proposed acquisition of Southern California Edison				40,000,000
Amortization period				10 years
Fixed costs recoverable per residential power lost								0.031
Fixed costs recoverable per non-residential power lost								0.023
Amount of adjustment approved representing prorated sales losses							$ 5,100,000