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 5 Current Assets 3 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 6 Cash and cash equivalents 4 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 true true 742600000 742.6 false false 2 true true 202200000 202.2 false false No definition available. No authoritative reference available. false 7 Accounts receivable (net of allowance for uncollectibles of $180.9 and $240.6, respectively) 4 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 2217100000 2217.1 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 8 Fuel stocks 4 us-gaap_EnergyRelatedInventory us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 303800000 303.8 false false 2 false true 717900000 717.9 false false No definition available. No authoritative reference available. false 9 Materials and supplies 4 us-gaap_OtherInventorySupplies us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 224400000 224.4 false false 2 false true 224500000 224.5 false false No definition available. No authoritative reference available. false 10 Derivative assets 4 us-gaap_DerivativeAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 582800000 582.8 false false 2 false true 1465000000 1465.0 false false No definition available. No authoritative reference available. false 11 Unamortized energy contract assets 4 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 89800000 89.8 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 12 Restricted cash 4 us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 48900000 48.9 false false 2 false true 1030500000 1030.5 false false No definition available. No authoritative reference available. false 13 Deferred income taxes 4 us-gaap_DeferredTaxAssetsNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 346000000 346.0 false false 2 false true 268000000 268.0 false false No definition available. No authoritative reference available. false 14 Other 4 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 264700000 264.7 false false 2 false true 815500000 815.5 false false No definition available. No authoritative reference available. false 15 Total current assets 4 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 4820100000 4820.1 false false 2 false true 8194800000 8194.8 false false No definition available. No authoritative reference available. true 16 Investments and Other Noncurrent Assets 3 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 17 Nuclear decommissioning trust funds 4 us-gaap_DecommissioningFundInvestments us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1200400000 1200.4 false false 2 false true 1006300000 1006.3 false false No definition available. No authoritative reference available. false 18 Other investments 4 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 350000000 350.0 false false 2 false true 421000000 421.0 false false No definition available. No authoritative reference available. false 19 Regulatory assets (net) 4 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 434100000 434.1 false false 2 false true 494700000 494.7 false false No definition available. No authoritative reference available. false 20 Goodwill 4 us-gaap_Goodwill us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 25400000 25.4 false false 2 false true 4600000 4.6 false false No definition available. No authoritative reference available. false 21 Derivative assets 4 us-gaap_DerivativeAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 917700000 917.7 false false 2 false true 851800000 851.8 false false No definition available. No authoritative reference available. false 22 Unamortized energy contract assets 4 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 212500000 212.5 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 4 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 292000000 292.0 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 4 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 3432100000 3432.1 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 3 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 Property, plant and equipment 4 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 16148000000 16148.0 false false 2 false true 15285600000 15285.6 false false No definition available. No authoritative reference available. false 27 Nuclear fuel (net of amortization) 4 us-gaap_NuclearFuelNetOfAmortization us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 528400000 528.4 false false 2 false true 443000000 443.0 false false No definition available. No authoritative reference available. false 28 Accumulated depreciation 4 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -5222600000 -5222.6 false false 2 false true -5012100000 -5012.1 false false No definition available. No authoritative reference available. false 29 Net property, plant and equipment 4 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 11453800000 11453.8 false false 2 false true 10716500000 10716.5 false false No definition available. No authoritative reference available. true 30 Total Assets 3 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 19706000000 19706.0 false false 2 false true 22284100000 22284.1 false false No definition available. No authoritative reference available. true 32 Current Liabilities 3 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 33 Short-term borrowings 4 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 334900000 334.9 false false 2 false true 855700000 855.7 false false No definition available. No authoritative reference available. false 34 Current portion of long-term debt 4 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1333600000 1333.6 false false 2 false true 2591500000 2591.5 false false No definition available. No authoritative reference available. false 35 Accounts payable and accrued liabilities 4 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1368900000 1368.9 false false 2 false true 2370100000 2370.1 false false No definition available. No authoritative reference available. false 36 Customer deposits and collateral 4 us-gaap_CustomerDepositsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 105400000 105.4 false false 2 false true 120300000 120.3 false false No definition available. No authoritative reference available. false 37 Derivative liabilities 4 us-gaap_DerivativeLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 823100000 823.1 false false 2 false true 1241800000 1241.8 false false No definition available. No authoritative reference available. false 38 Unamortized energy contract liabilities 4 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 397400000 397.4 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 39 Accrued expenses 4 us-gaap_AccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 393900000 393.9 false false 2 false true 373100000 373.1 false false No definition available. No authoritative reference available. false 40 Other 4 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 447700000 447.7 false false 2 false true 514200000 514.2 false false No definition available. No authoritative reference available. false 41 Total current liabilities 4 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 5204900000 5204.9 false false 2 false true 8460200000 8460.2 false false No definition available. No authoritative reference available. true 42 Deferred Credits and Other Noncurrent Liabilities 3 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 43 Deferred income taxes 4 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1223200000 1223.2 false false 2 false true 677000000 677.0 false false No definition available. No authoritative reference available. false 44 Asset retirement obligations 4 us-gaap_AssetRetirementObligationsNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1040800000 1040.8 false false 2 false true 987300000 987.3 false false No definition available. No authoritative reference available. false 45 Derivative liabilities 4 us-gaap_DerivativeLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 964800000 964.8 false false 2 false true 1115000000 1115.0 false false No definition available. No authoritative reference available. false 46 Unamortized energy contract liabilities 4 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 682300000 682.3 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 47 Defined benefit obligations 4 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 1049500000 1049.5 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 48 Deferred investment tax credits 4 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 39600000 39.6 false false 2 false true 44100000 44.1 false false No definition available. No authoritative reference available. false 49 Other 4 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 365800000 365.8 false false 2 false true 249600000 249.6 false false No definition available. No authoritative reference available. false 50 Total deferred credits and other noncurrent liabilities 4 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 5366000000 5366.0 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 51 Long-term Debt, Net of Current Portion 3 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4839600000 4839.6 false false 2 false true 5098700000 5098.7 false false No definition available. No authoritative reference available. false 53 Common shareholders' equity: 4 us-gaap_EquityAbstract 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 54 Common stock 5 us-gaap_CommonStockValue us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 3213000000 3213.0 false false 2 false true 3164500000 3164.5 false false No definition available. No authoritative reference available. false 55 Retained earnings 5 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2089400000 2089.4 false false 2 false true 2228700000 2228.7 false false No definition available. No authoritative reference available. false 56 Accumulated other comprehensive loss 5 us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -1269400000 -1269.4 false false 2 false true -2211800000 -2211.8 false false No definition available. No authoritative reference available. false 57 Total common shareholders' equity 5 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 4033000000 4033.0 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. true 58 BGE preference stock not subject to mandatory redemption 4 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 59 Noncontrolling interests 4 us-gaap_MinorityInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 72500000 72.5 false false 2 false true 20100000 20.1 false false No definition available. No authoritative reference available. false 60 Total equity 4 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4295500000 4295.5 false false 2 false true 3391500000 3391.5 false false No definition available. No authoritative reference available. true 61 Commitments and Contingencies (see Notes) 3 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 62 Total Liabilities and Equity 3 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 true true 19706000000 19706.0 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