2.2.0.25falsefalse0216 - Disclosure - Asset Retirement Obligationstruefalsefalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) USD ($) / shares $Jan-01-2011_Mar-31-2011http://www.sec.gov/CIK0000764622duration2011-01-01T00:00:002011-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0us-gaap_AssetRetirementObligationAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseAsset Retirement Obligations [Abstract]3false0us-gaap_AssetRetirementObligationDisclosureTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" --> <!-- Begin Block Tagged Note 16 - us-gaap:AssetRetirementObligationDisclosureTextBlock--> <div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "> <div align="left" style="font-size: 10pt; margin-top: 10pt"><b>16. Asset Retirement Obligations</b> </div> <div align="left" style="font-size: 10pt; margin-top: 10pt; text-indent: 4%">APS has asset retirement obligations for its Palo Verde nuclear facilities and certain other generation, transmission and distribution assets. During the period ending March&#160;31, 2011, a new decommissioning study with updated cash flow estimates was completed for Palo Verde. This study reflects the twenty-year license extension approved by the NRC on April&#160;21, 2011, which extends the commencement of decommissioning to 2045. The new study resulted in a $90&#160;million decrease to the liability for asset retirements, a $78&#160;million decrease to electric plant in service, and a $12&#160;million increase to regulatory liabilities. </div> <!-- Folio --> <!-- /Folio --> </div> <!-- PAGEBREAK --> <div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "> <div align="center" style="font-size: 10pt; margin-top: 0pt"> <b> </b> </div> </div> <!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" --> <!-- Begin Block Tagged NotefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescription of the asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. This element may be used for all the disclosures related to asset retirement obligations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 143 -Paragraph 22 falsefalseAsset Retirement Obligations12Asset Retirement ObligationsUnKnownUnKnownUnKnownUnKnownfalsetrue