Commitments and Contingencies (Details 3) (ARIZONA PUBLIC SERVICE COMPANY, USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Four Corners
Environmental Matters
Expected environmental cost	$ 300
Navajo Plant
Environmental Matters
Expected environmental cost	158
Cholla
Environmental Matters
Expected environmental cost	187
Cholla Units 1-3
Environmental Matters
Expected environmental cost	$ 124

Best estimate of the loss exposure for reasonably possible environmental contingencies at an individual site for which no accrual has been recorded.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 96-1

-Paragraph 163

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 10

-Subparagraph (c),(d)(2)

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration