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 961600000 961.6 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 $260.2 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 2429200000 2429.2 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 310200000 310.2 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 222300000 222.3 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 1036400000 1036.4 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 138000000 138.0 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 26000000 26.0 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 290200000 290.2 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 240500000 240.5 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 5654400000 5654.4 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 1079800000 1079.8 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 333600000 333.6 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 454500000 454.5 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 4600000 4.6 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 747200000 747.2 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 223900000 223.9 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 312200000 312.2 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 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 3155800000 3155.8 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 15817700000 15817.7 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 482400000 482.4 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 -5111900000 -5111.9 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 11188200000 11188.2 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 19998400000 19998.4 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 339900000 339.9 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 1830600000 1830.6 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 1582500000 1582.5 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 114900000 114.9 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 1272800000 1272.8 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 428700000 428.7 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 278300000 278.3 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 456600000 456.6 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 6304300000 6304.3 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 937100000 937.1 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 1022600000 1022.6 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 937500000 937.5 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 853700000 853.7 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 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 1061300000 1061.3 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 41100000 41.1 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 256000000 256.0 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 5109300000 5109.3 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 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 4817000000 4817.0 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 3191500000 3191.5 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 2002700000 2002.7 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 -1662300000 -1662.3 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 3531900000 3531.9 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 45900000 45.9 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 3767800000 3767.8 false false 2 false true 3391500000 3391.5 false false No definition available. No authoritative reference available. true 61 Commitments, Guarantees, 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 19998400000 19998.4 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