Retirement Plans and Other Benefits (Details) (USD $)	3 Months Ended	12 Months Ended				12 Months Ended
	Mar. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2012 Pension Benefits	Dec. 31, 2011 Pension Benefits	Dec. 31, 2010 Pension Benefits	Dec. 31, 2012 Pension Benefits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 Pension Benefits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2010 Pension Benefits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2012 Other Benefits	Dec. 31, 2011 Other Benefits	Dec. 31, 2010 Other Benefits	Dec. 31, 2012 Other Benefits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2011 Other Benefits ARIZONA PUBLIC SERVICE COMPANY	Dec. 31, 2010 Other Benefits ARIZONA PUBLIC SERVICE COMPANY
Retirement Plans and Other Benefits
Change in regulatory assets	$ 42,000,000
Increase in accumulated deferred income tax liabilities		(69,000,000)		(69,000,000)
Amount of pension and other postretirement benefit costs deferred		14,000,000	11,000,000
Net periodic benefit costs and the portion of these costs charged to expense
Service cost - benefits earned during the period						63,502,000	57,605,000	59,064,000				27,163,000	21,856,000	19,236,000
Interest cost on benefit obligation						119,586,000	124,727,000	122,724,000				46,467,000	46,807,000	42,428,000
Expected return on plan assets						(140,979,000)	(133,678,000)	(124,161,000)				(45,793,000)	(41,536,000)	(39,257,000)
Amortization of transition obligation												452,000	452,000	452,000
Amortization of prior service cost (credit)						1,143,000	1,400,000	1,705,000				(179,000)	(179,000)	(539,000)
Amortization of net actuarial loss						44,250,000	25,956,000	18,833,000				20,233,000	15,015,000	10,317,000
Net periodic benefit cost						87,502,000	76,010,000	78,165,000				48,343,000	42,415,000	32,637,000
Portion of cost charged to expense						36,333,000	29,312,000	37,933,000				19,321,000	15,208,000	15,839,000
Change in Benefit Obligation
Benefit obligation at the beginning of the period						2,699,126,000	2,345,060,000					1,047,094,000	827,897,000
Service cost						63,502,000	57,605,000	59,064,000				27,163,000	21,856,000	19,236,000
Interest cost						119,586,000	124,727,000	122,724,000				46,467,000	46,807,000	42,428,000
Benefit payments						(113,632,000)	(104,257,000)					(26,279,000)	(24,877,000)
Actuarial (gain) loss						82,264,000	275,991,000					(104,027,000)	171,674,000
Plan amendments													3,737,000
Benefit obligation at the end of the period						2,850,846,000	2,699,126,000	2,345,060,000				990,418,000	1,047,094,000	827,897,000
Funded Status at the end of the period						(771,665,000)	(848,576,000)					(306,197,000)	(438,431,000)
Change in Plan Assets
Balance at the beginning of the period						1,850,550,000	1,775,596,000					608,663,000	567,410,000
Actual return on plan assets						259,363,000	162,042,000					83,567,000	58,367,000
Employer contributions						65,000,000		200,000,000	64,000,000	0	195,000,000	22,707,000	18,769,000	17,000,000	22,000,000	19,000,000	16,000,000
Benefit payments						(95,732,000)	(87,088,000)					(30,716,000)	(35,883,000)
Balance at the end of the period						2,079,181,000	1,850,550,000	1,775,596,000				684,221,000	608,663,000	567,410,000
Funded Status at the end of the period						(771,665,000)	(848,576,000)					(306,197,000)	(438,431,000)
Projected benefit obligation and the accumulated benefit obligation for pension plans with an accumulated obligation in excess of plan assets
Projected benefit obligation						2,850,846,000	2,699,126,000
Accumulated benefit obligation						2,646,306,000	2,396,575,000
Fair value of plan assets						2,079,181,000	1,850,550,000
Amounts recognized on the Consolidated Balance Sheets
Current liability						(19,107,000)	(18,097,000)
Noncurrent liability		(1,058,755,000)	(1,268,910,000)	(1,017,556,000)	(1,222,542,000)	(752,558,000)	(830,479,000)					(306,197,000)	(438,431,000)
Net amount recognized						(771,665,000)	(848,576,000)					(306,197,000)	(438,431,000)
Regulatory asset amortization period		3 years
Amortization of regulatory assets		$ 4,000,000