Income Taxes (APSC) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2010	Sep. 30, 2009	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income taxes
Long-term income tax receivables			$ 70,389,000	$ 68,633,000
Period over which the cash refunds are not expected to be received		12 months
Settlements with taxing authorities	62,000,000			124,000	62,199,000
Net decrease in uncertain tax positions which decreased our effective tax rate	3,000,000
Net interest benefits through the effective tax rate	4,000,000
Tabular reconciliation of the total amounts of unrecognized tax benefits, excluding interest and penalties, at the beginning and end of the year
Total unrecognized tax benefits at the beginning of the year	201,216,000		136,005,000	127,595,000	201,216,000
Additions for tax positions of the current year			5,167,000	10,915,000	7,551,000
Reductions for tax positions of prior years for:
Changes in judgment			(7,729,000)	(1,555,000)	(11,017,000)
Settlements with taxing authorities	(62,000,000)			(124,000)	(62,199,000)
Lapses of applicable statute of limitations			(21,000)	(826,000)	(7,956,000)
Total unrecognized tax benefits at the end of the year			133,422,000	136,005,000	127,595,000
Unrecognized tax benefits if recognized, would decrease effective tax rate			10,000,000	8,000,000	7,000,000
Pre-tax interest expense (benefit) related to unrecognized tax benefits			4,000,000	3,000,000	(2,000,000)
Accrued liabilities for interest related to unrecognized tax benefits			13,000,000	9,000,000	6,000,000
Interest income to be received on the overpayment of income taxes for certain adjustments that we have filed, or will file, with the IRS			5,000,000
ARIZONA PUBLIC SERVICE COMPANY
Income taxes
Long-term income tax receivables		71,000,000	70,784,000	69,028,000
Period over which the cash refunds are not expected to be received		12 months
Settlements with taxing authorities	62,000,000			124,000	61,820,000
Net decrease in uncertain tax positions which decreased our effective tax rate	3,000,000
Net interest benefits through the effective tax rate	4,000,000
Tabular reconciliation of the total amounts of unrecognized tax benefits, excluding interest and penalties, at the beginning and end of the year
Total unrecognized tax benefits at the beginning of the year	199,887,000		135,824,000	126,698,000	199,887,000
Additions for tax positions of the current year			5,167,000	10,915,000	7,551,000
Reductions for tax positions of prior years for:
Changes in judgment			(7,729,000)	(1,555,000)	(10,964,000)
Settlements with taxing authorities	(62,000,000)			(124,000)	(61,820,000)
Lapses of applicable statute of limitations			(21,000)	(110,000)	(7,956,000)
Total unrecognized tax benefits at the end of the year			133,241,000	135,824,000	126,698,000
Unrecognized tax benefits if recognized, would decrease effective tax rate			10,000,000	8,000,000	6,000,000
Pre-tax interest expense (benefit) related to unrecognized tax benefits			4,000,000	3,000,000	(2,000,000)
Accrued liabilities for interest related to unrecognized tax benefits			13,000,000	9,000,000	6,000,000
Interest income to be received on the overpayment of income taxes for certain adjustments that we have filed, or will file, with the IRS			$ 5,000,000