1.0.0.3 false CONSOLIDATED BALANCE SHEETS (Constellation Energy Group, Inc. and Subsidiaries) (USD $) In Millions false 1 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 2 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 4 Current Assets 2 us-gaap_AssetsCurrentAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 5 Cash and cash equivalents 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 true true 3440000000 3440.0 false false 2 true true 202200000 202.2 false false No definition available. No authoritative reference available. false 6 Accounts receivable (net of allowance for uncollectibles of $160.6 and $240.6, respectively) 3 ceg_AccountsReceivableNetCurrentParent ceg false debit instant monetary Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is ... false false false false false false false false false 1 false true 2137600000 2137.6 false false 2 false true 3389900000 3389.9 false false Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Also includes amounts related to exchange-traded derivatives including related margin postings. No authoritative reference available. false 7 Fuel stocks 3 us-gaap_EnergyRelatedInventory us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 314900000 314.9 false false 2 false true 717900000 717.9 false false No definition available. No authoritative reference available. false 8 Materials and supplies 3 us-gaap_OtherInventorySupplies us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 93300000 93.3 false false 2 false true 224500000 224.5 false false No definition available. No authoritative reference available. false 9 Derivative assets 3 us-gaap_DerivativeAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 639100000 639.1 false false 2 false true 1465000000 1465.0 false false No definition available. No authoritative reference available. false 10 Unamortized energy contract assets (includes $371.3 million related to CENG) 3 ceg_UnamortizedEnergyContractAssetsCurrent ceg false debit instant monetary Current portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives... false false false false false false false false false 1 false true 436500000 436.5 false false 2 false true 81300000 81.3 false false Current portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives designated as normal purchases and normal sales previously recorded as "Derivative assets." No authoritative reference available. false 11 Restricted cash 3 us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 27000000 27.0 false false 2 false true 1030500000 1030.5 false false No definition available. No authoritative reference available. false 12 Deferred income taxes 3 us-gaap_DeferredTaxAssetsNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 127900000 127.9 false false 2 false true 268000000 268.0 false false No definition available. No authoritative reference available. false 13 Other 3 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 244400000 244.4 false false 2 false true 815500000 815.5 false false No definition available. No authoritative reference available. false 14 Total current assets 3 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 7460700000 7460.7 false false 2 false true 8194800000 8194.8 false false No definition available. No authoritative reference available. true 15 Investments and Other Noncurrent Assets 2 ceg_InvestmentsAndOtherNoncurrentAssetsAbstract ceg false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 16 Nuclear decommissioning trust funds 3 us-gaap_DecommissioningFundInvestments us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 false false 2 false true 1006300000 1006.3 false false No definition available. No authoritative reference available. false 17 Investment in CENG 3 ceg_InvestmentInCENG ceg false debit instant monetary Total investment in Consolidated Energy Nuclear Group, LLC. false false false false false false false false false 1 false true 5222900000 5222.9 false false 2 false false 0 0 false false Total investment in Consolidated Energy Nuclear Group, LLC. No authoritative reference available. false 18 Other investments 3 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 424300000 424.3 false false 2 false true 421000000 421.0 false false No definition available. No authoritative reference available. false 19 Regulatory assets (net) 3 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 414400000 414.4 false false 2 false true 494700000 494.7 false false No definition available. No authoritative reference available. false 20 Goodwill 3 us-gaap_Goodwill us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 25500000 25.5 false false 2 false true 4600000 4.6 false false No definition available. No authoritative reference available. false 21 Derivative assets 3 us-gaap_DerivativeAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 633900000 633.9 false false 2 false true 851800000 851.8 false false No definition available. No authoritative reference available. false 22 Unamortized energy contract assets (includes $400.9 million related to CENG) 3 ceg_UnamortizedEnergyContractAssetsNoncurrent ceg false debit instant monetary NonCurrent portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives... false false false false false false false false false 1 false true 604700000 604.7 false false 2 false true 173100000 173.1 false false NonCurrent portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives designated as normal purchases and normal sales previously recorded as "Derivative assets." No authoritative reference available. false 23 Other 3 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 304200000 304.2 false false 2 false true 421300000 421.3 false false No definition available. No authoritative reference available. false 24 Total investments and other noncurrent assets 3 ceg_InvestmentsAndOtherNoncurrentAssets ceg false debit instant monetary Sum of the carrying amount of all investments and other assets that are expected to be realized or consumed after one year... false false false false false false false false false 1 false true 7629900000 7629.9 false false 2 false true 3372800000 3372.8 false false Sum of the carrying amount of all investments and other assets that are expected to be realized or consumed after one year (or the normal operating cycle, if longer), excluding property, plant & equipment. No authoritative reference available. true 25 Property, Plant and Equipment 2 us-gaap_PropertyPlantAndEquipmentAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 26 Nonregulated property, plant and equipment 3 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 5784600000 5784.6 false false 2 false true 8866200000 8866.2 false false No definition available. No authoritative reference available. false 27 Regulated property, plant and equipment 3 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 6749900000 6749.9 false false 2 false true 6419400000 6419.4 false false No definition available. No authoritative reference available. false 28 Nuclear fuel (net of amortization) 3 us-gaap_NuclearFuelNetOfAmortization us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false false 0 0 false false 2 false true 443000000 443.0 false false No definition available. No authoritative reference available. false 29 Accumulated depreciation 3 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -4080700000 -4080.7 false false 2 false true -5012100000 -5012.1 false false No definition available. No authoritative reference available. false 30 Net property, plant and equipment 3 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 8453800000 8453.8 false false 2 false true 10716500000 10716.5 false false No definition available. No authoritative reference available. true 31 Total Assets 2 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 23544400000 23544.4 false false 2 false true 22284100000 22284.1 false false No definition available. No authoritative reference available. true 33 Current Liabilities 2 us-gaap_LiabilitiesCurrentAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 34 Short-term borrowings 3 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 46000000 46.0 false false 2 false true 855700000 855.7 false false No definition available. No authoritative reference available. false 35 Current portion of long-term debt 3 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 56900000 56.9 false false 2 false true 2591500000 2591.5 false false No definition available. No authoritative reference available. false 36 Accounts payable and accrued liabilities 3 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1262400000 1262.4 false false 2 false true 2370100000 2370.1 false false No definition available. No authoritative reference available. false 37 Customer deposits and collateral 3 us-gaap_CustomerDepositsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 103300000 103.3 false false 2 false true 120300000 120.3 false false No definition available. No authoritative reference available. false 38 Derivative liabilities 3 us-gaap_DerivativeLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 632600000 632.6 false false 2 false true 1241800000 1241.8 false false No definition available. No authoritative reference available. false 39 Unamortized energy contract liabilities 3 ceg_UnamortizedEnergyContractLiabilitiesCurrent ceg false credit instant monetary Current portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives... false false false false false false false false false 1 false true 390100000 390.1 false false 2 false true 393500000 393.5 false false Current portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives designated as normal purchases and normal sales previously recorded as "Derivative liabilities." No authoritative reference available. false 40 Accrued taxes 3 us-gaap_TaxesPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 877300000 877.3 false false 2 false true 51100000 51.1 false false No definition available. No authoritative reference available. false 41 Accrued expenses 3 us-gaap_AccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 297900000 297.9 false false 2 false true 322000000 322.0 false false No definition available. No authoritative reference available. false 42 Other 3 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 374200000 374.2 false false 2 false true 514200000 514.2 false false No definition available. No authoritative reference available. false 43 Total current liabilities 3 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4040700000 4040.7 false false 2 false true 8460200000 8460.2 false false No definition available. No authoritative reference available. true 44 Deferred Credits and Other Noncurrent Liabilities 2 ceg_DeferredCreditsAndOtherNoncurrentLiabilitiesAbstract ceg false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 45 Deferred income taxes 3 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 3205500000 3205.5 false false 2 false true 677000000 677.0 false false No definition available. No authoritative reference available. false 46 Asset retirement obligations 3 us-gaap_AssetRetirementObligationsNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 29300000 29.3 false false 2 false true 987300000 987.3 false false No definition available. No authoritative reference available. false 47 Derivative liabilities 3 us-gaap_DerivativeLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 674100000 674.1 false false 2 false true 1115000000 1115.0 false false No definition available. No authoritative reference available. false 48 Unamortized energy contract liabilities 3 ceg_UnamortizedEnergyContractLiabilitiesNoncurrent ceg false credit instant monetary NonCurrent portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives... false false false false false false false false false 1 false true 653700000 653.7 false false 2 false true 906400000 906.4 false false NonCurrent portion of remaining unamortized balance of non-derivative energy contracts that we acquired or derivatives designated as normal purchases and normal sales previously recorded as "Derivative liabilities." No authoritative reference available. false 49 Defined benefit obligations 3 ceg_DefinedBenefitObligations ceg false credit instant monetary For classified balance sheets this represents the noncurrent liability for underfunded plans recognized in the balance sheet... false false false false false false false false false 1 false true 743900000 743.9 false false 2 false true 1354300000 1354.3 false false For classified balance sheets this represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans, other postretirement defined benefit plans and other postemployment benefits (i.e. benefits for disabled and their dependents). No authoritative reference available. false 50 Deferred investment tax credits 3 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 32000000 32.0 false false 2 false true 44100000 44.1 false false No definition available. No authoritative reference available. false 51 Other 3 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 388800000 388.8 false false 2 false true 249600000 249.6 false false No definition available. No authoritative reference available. false 52 Total deferred credits and other noncurrent liabilities 3 ceg_DeferredCreditsAndOtherNoncurrentLiabilities ceg false credit instant monetary Sum of carrying amount of deferred credits and other liabilities that are expected to be repaid beyond the following 12... false false false false false false false false false 1 false true 5727300000 5727.3 false false 2 false true 5333700000 5333.7 false false Sum of carrying amount of deferred credits and other liabilities that are expected to be repaid beyond the following 12 months or business cycle. No authoritative reference available. true 53 Long-term Debt, Net of Current Portion 2 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4814000000 4814.0 false false 2 false true 5098700000 5098.7 false false No definition available. No authoritative reference available. false 54 Equity 2 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 55 Common shareholders' equity 3 ceg_CommonShareholdersEquity ceg false credit instant monetary Sum of the carrying amounts as of the balance sheet date of common stock, retained earnings, and accumulated other... false false false false false false false false false 1 false true 8697100000 8697.1 false false 2 false true 3181400000 3181.4 false false Sum of the carrying amounts as of the balance sheet date of common stock, retained earnings, and accumulated other comprehensive income/loss. No authoritative reference available. false 56 BGE preference stock not subject to mandatory redemption 3 us-gaap_PreferredStockValue us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 190000000 190.0 false false 2 false true 190000000 190.0 false false No definition available. No authoritative reference available. false 57 Noncontrolling interests 3 us-gaap_MinorityInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 75300000 75.3 false false 2 false true 20100000 20.1 false false No definition available. No authoritative reference available. false 58 Total equity 3 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 8962400000 8962.4 false false 2 false true 3391500000 3391.5 false false No definition available. No authoritative reference available. true 59 Commitments, Guarantees, and Contingencies (see Note 12) 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. No authoritative reference available. false 60 Total Liabilities and Equity 2 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 true true 23544400000 23544.4 false false 2 true true 22284100000 22284.1 false false No definition available. No authoritative reference available. true false 2 56 false HundredThousands UnKnown UnKnown false true