2.2.0.7 true Fair Value Measurements (Reconciliation of the beginning and ending net balances for assets and liabilities measured at Level 3 fair value) (Details) (USD $) 41203 - Disclosure - Fair Value Measurements (Reconciliation of the beginning and ending net balances for assets and liabilities measured at Level 3 fair value) (Details) true false In Millions false false 1 USD false false Unit12 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 Unit13 Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 2 USD false false Unit12 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 $ false 3 USD false false Unit12 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 Unit13 Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 4 USD false false Unit12 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 $ false 5 USD true false false false Fair Value Commodity [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueCommodityMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false Fair Value Commodity [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueCommodityMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 7 USD true false false false Fair Value Interest Rate Contract [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueInterestRateContractMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false Fair Value Interest Rate Contract [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueInterestRateContractMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 9 USD true false false false Fair Value Other Derivative [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueOtherDerivativeMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 10 USD true false false false Fair Value Other Derivative [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueOtherDerivativeMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 11 USD true false false false Energy [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_EnergyMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 12 USD true false false false Energy [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_EnergyMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 13 USD true false false false Financial & other [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FinancialOtherMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 14 USD true false false false Financial & other [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FinancialOtherMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 15 USD true false false false Fair Value Other [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueOtherMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 16 USD true false false false Fair Value Other [Member] us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis xbrldi http://xbrl.org/2006/xbrldi ed_FairValueOtherMember us-gaap_FairValueEstimateNotPracticableDisclosureItemsAxis explicitMember Unit12 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 5 Beginning Balance 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue us-gaap true debit instant No definition available. false false false false false false false false true false false periodstartlabel false 1 true true false false -19000000 -19 false false false 2 true true false false -15000000 -15 false false false 3 true true false false 22000000 22 false false false 4 true true false false 8000000 8 false false false 5 true true false false -101000000 -101 true false false 6 true true false false -59000000 -59 true false false 7 true true false false -11000000 -11 true false false 8 true true false false -12000000 -12 true false false 9 true true false false 94000000 94 [1] true false false 10 true true false false 92000000 92 [1] true false false 11 true true false false -85000000 -85 true false false 12 true true false false -50000000 -50 true false false 13 true true false false -15000000 -15 true false false 14 true true false false -12000000 -12 true false false 15 true true false false 82000000 82 true false false 16 true true false false 73000000 73 true false false xbrli:monetaryItemType monetary This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c false 6 Included in Earnings 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false -45000000 -45 false false false 2 false true false false -105000000 -105 false false false 3 false true false false -97000000 -97 false false false 4 false true false false -207000000 -207 false false false 5 false true false false -45000000 -45 true false false 6 false true false false -95000000 -95 true false false 7 false true false false -2000000 -2 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false true false false -108000000 -108 true false false 12 false true false false -213000000 -213 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false true false false 3000000 3 true false false 16 false true false false 6000000 6 true false false xbrli:monetaryItemType monetary This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(1) false 7 Included in Regulatory Assets and Liabilities 3 ed_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIncludedInRegulatoryAssetsAndLiabilities ed false debit duration Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Included In regulatory Assets And... false false false false false false false false false false false terselabel false 1 false true false false -10000000 -10 false false false 2 false true false false 59000000 59 false false false 3 false true false false -52000000 -52 false false false 4 false true false false 17000000 17 false false false 5 false true false false -12000000 -12 true false false 6 false true false false -55000000 -55 true false false 7 false true false false -1000000 -1 true false false 8 false false false false 0 0 true false false 9 false true false false 2000000 2 [1] true false false 10 false true false false 4000000 4 [1] true false false 11 false true false false 56000000 56 true false false 12 false true false false 5000000 5 true false false 13 false true false false 3000000 3 true false false 14 false false false false 0 0 true false false 15 false true false false 3000000 3 true false false 16 false true false false 9000000 9 true false false xbrli:monetaryItemType monetary Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Included In regulatory Assets And Liabilities No authoritative reference available. false 8 Purchases, Issuances, Sales and Settlements 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 16000000 16 false false false 2 false true false false 81000000 81 false false false 3 false true false false 46000000 46 false false false 4 false true false false 202000000 202 false false false 5 false true false false 16000000 16 true false false 6 false true false false 44000000 44 true false false 7 false true false false 2000000 2 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false true false false 81000000 81 true false false 12 false true false false 202000000 202 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false 16 false false false false 0 0 true false false xbrli:monetaryItemType monetary This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(2) false 9 Transfers In/Out of Level 3 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false -2000000 -2 false false false 2 false true false false -1000000 -1 false false false 3 false true false false 21000000 21 false false false 4 false true false false -1000000 -1 false false false 5 false true false false -2000000 -2 true false false 6 false true false false 21000000 21 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false true false false -1000000 -1 true false false 12 false true false false -1000000 -1 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false 16 false false false false 0 0 true false false xbrli:monetaryItemType monetary This element represents [net] transfers in to and out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(3) false 10 Ending Balance 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue us-gaap true debit instant No definition available. false false false false false false false false false true false periodendlabel false 1 true true false false -60000000 -60 false false false 2 true true false false 19000000 19 false false false 3 true true false false -60000000 -60 false false false 4 true true false false 19000000 19 false false false 5 true true false false -144000000 -144 true false false 6 true true false false -144000000 -144 true false false 7 true true false false -12000000 -12 true false false 8 true true false false -12000000 -12 true false false 9 true true false false 96000000 96 [1] true false false 10 true true false false 96000000 96 [1] true false false 11 true true false false -57000000 -57 true false false 12 true true false false -57000000 -57 true false false 13 true true false false -12000000 -12 true false false 14 true true false false -12000000 -12 true false false 15 true true false false 88000000 88 true false false 16 true true false false 88000000 88 true false false xbrli:monetaryItemType monetary This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c false 1 Amounts included in earnings are reported in investment and other income on the consolidated income statement. 16 6 false Millions UnKnown UnKnown false true