Income Taxes (Details) (USD $)	0 Months Ended	3 Months Ended
Sep. 13, 2013	Mar. 31, 2015
Income Taxes
Increase (decrease) in deferred income taxes due to adoption of regulations	$ 82,000,000
Consolidation of VIEs
Income Taxes
Income tax expense associates with the VIE's		$ 0

The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa, due to the adoption of regulations.

No definition available.

Name:	pnw_IncreaseDecreaseInDeferredIncomeTaxesDueToRegulationAdoption
Namespace Prefix:	pnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration