Derivative Accounting Narrative (Details) (USD $)					9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Arizona Public Service Company	Sep. 30, 2014 Designated as Hedging Instruments	Dec. 31, 2013 Designated as Hedging Instruments	Sep. 30, 2014 Commodity Contracts Counterparty	Dec. 31, 2013 Commodity Contracts	Sep. 30, 2014 Commodity Contracts Designated as Hedging Instruments	Sep. 30, 2013 Commodity Contracts Designated as Hedging Instruments	Sep. 30, 2014 Commodity Contracts Designated as Hedging Instruments	Sep. 30, 2013 Commodity Contracts Designated as Hedging Instruments
Derivative Accounting
Percentage of deferred unrealized gains (losses) on contracts due to PSA recovery	100.00%
Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment	100.00%	100.00%
Amount reclassified from accumulated other comprehensive income to earnings related to discontinued cash flow hedges							$ 0	$ 0	$ 0	$ 0
Estimated net gain (loss) before income taxes to be reclassified from accumulated other comprehensive income									(9,000,000)
Gross recognized derivatives			4,000,000	5,000,000	92,429,000	122,663,000
Amounts offset					(40,101,000)	(19,000,000)
Derivative liability, not subject to master netting arrangement					7,743,000	7,518,000
Other					481,000	7,000
Concentration of credit risk, number of counterparties					2
Concentration of risk with two counterparties, as a percentage of risk management assets					89.00%
Risk management activities-derivative instruments: Commodity Contracts					29,301,000	40,984,000
Additional collateral to counterparties for energy related non-derivative instrument contracts					$ 175,000,000