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Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 false 109 Equity securities-mutual funds 2 ceg_EquitySecuritiesMutualFunds ceg false debit instant This element represents the investment that pools funds from many investors to invest in a combination of underlying... false false false false false false false false false false false terselabel false 1 false true false false 46200000 46.2 false false false xbrli:monetaryItemType monetary This element represents the investment that pools funds from many investors to invest in a combination of underlying investments, primarily mutual funds. No authoritative reference available. false 118 Derivative assets, gross 2 us-gaap_DerivativeFairValueOfDerivativeAsset 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 924300000 924.3 false false false xbrli:monetaryItemType monetary Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 false 120 Derivative liabilities, gross 2 us-gaap_DerivativeFairValueOfDerivativeLiability us-gaap true credit instant No definition available. false false false false false false false false false false true negated false 1 false true false false -1306700000 -1306.7 false false false xbrli:monetaryItemType monetary Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 false 121 Net derivative position 2 us-gaap_DerivativeFairValueOfDerivativeNet 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 -382400000 -382.4 false false false xbrli:monetaryItemType monetary Fair value as of the balance sheet date of the assets less the liabilities of a derivative or group of derivatives. No authoritative reference available. false 122 Assets and liabilities, net, measured at fair value on a recurring basis 2 ceg_FairValueAssetsAndLiabilitiesNetMeasuredOnRecurringBasis ceg false debit instant Represents the net amount of assets and liabilities measured at fair value on a recurring basis. false false false false false false false false false false false terselabel false 1 true true false false 2729200000 2729.2 false false false xbrli:monetaryItemType monetary Represents the net amount of assets and liabilities measured at fair value on a recurring basis. No authoritative reference available. false 1 Represents the unrealized fair value of exchange traded derivatives, exclusive of cash margin posted. 2 Represents in-the-money contracts without regard to potentially offsetting out-of-the-money contracts under master netting agreements. 3 Represents out-of-the-money contracts without regard to potentially offsetting in-the-money contracts under master netting agreements. 1 52 false HundredThousands UnKnown UnKnown false true