2.2.0.7 true Fair Value of Financial Assets and Liabilities (Table1) (Details) (USD $) 40802 - Disclosure - Fair Value of Financial Assets and Liabilities (Table1) (Details) true false In Millions false false 1 USD false false Unit13 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit12 Standard http://www.xbrl.org/2003/instance pure xbrli 0 Unit14 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit1 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false Unit13 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit14 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit1 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 3 Nuclear decommissioning trust fund equity securities 2 us-gaap_DecommissioningFundInvestments us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 true true false false 1884000000 1884 false false false 2 true true false false 1765000000 1765 false false false xbrli:monetaryItemType monetary Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. 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No authoritative reference available. false 12 Investments in available-for-sale auction rate securities 2 us-gaap_OtherShortTermInvestments us-gaap true debit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 177000000 177 [1],[2] false false false 2 false true false false 198000000 198 [1],[2] false false false xbrli:monetaryItemType monetary Other investments not otherwise specified in the taxonomy that will be realized in a short period of time, usually less than one year or the normal operating cycle, whichever is longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Subsection I Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph g -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 5 -Article 9 false 13 Nuclear decommissioning trust fund equity securities 2 us-gaap_DecommissioningFundInvestments us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 1222000000 1222 [2] false false false 2 false true false false 1156000000 1156 [2] false false false xbrli:monetaryItemType monetary Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. 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Such securities are reported at fair value; unrealized gains and losses of such securities are excluded from earnings and included in other comprehensive income, a separate component of shareholders' equity, unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Subsection I Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph g -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 5 -Article 9 false 43 Nuclear decommissioning trust fund equity securities 2 us-gaap_DecommissioningFundInvestments us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 5000000 5 [2] false false false 2 false false false false 0 0 false false false xbrli:monetaryItemType monetary Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. 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