2.2.0.7 true Investments (Details 2) (USD $) 4041 - Disclosure - Investments (Details 2) true false In Millions false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 4 Amortization of basis difference in CENG, pre-tax 2 ceg_AmortizationOfBasisDifferenceInInvestmentInAffiliatePreTax ceg false debit duration Amount of amortization of the basis difference in investment in affiliate. The basis difference represents the difference... false false false false false false false false false false true negated false 1 true true false false -29600000 -29.6 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Amount of amortization of the basis difference in investment in affiliate. The basis difference represents the difference between the fair value of our investment in affiliate less our share of the affiliate's equity because the affiliate's assets and liabilities retained their historical carrying value. No authoritative reference available. false 5 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 false true false false -6100000 -6.1 false false false 2 false true false false 76400000 76.4 false false false 3 false true false false 8100000 8.1 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 6 CEP 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosureinvestmentsdetails2 false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 4 USD true false false false CEP us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CEPMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 5 USD true false false false CEP us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CEPMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false CEP us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CEPMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 7 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 10 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 false true false false -4600000 -4.6 false false false 2 false true false false 7700000 7.7 false false false 3 false true false false 6100000 6.1 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 11 CENG 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosureinvestmentsdetails2 false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 7 USD true false false false CENG us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CENGMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false CENG us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CENGMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 9 USD true false false false CENG us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_CENGMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 12 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 13 CENG - equity investment earnings before adjustments for amortization of basis difference 2 ceg_IncomeLossFromEquityMethodInvestmentsBeforeAmortizationOfBasisDifferenceInAffiliatePreTax ceg false credit duration This element represents investments in affiliates before adjustment for amortization of basis difference. false false false false false false false false false false false terselabel false 1 false true false false 33900000 33.9 false false false 2 false false false false 0 0   false false false 3 false false false false 0 0   false false false xbrli:monetaryItemType monetary This element represents investments in affiliates before adjustment for amortization of basis difference. No authoritative reference available. false 14 Amortization of basis difference in CENG, pre-tax 2 ceg_AmortizationOfBasisDifferenceInInvestmentInAffiliatePreTax ceg false debit duration Amount of amortization of the basis difference in investment in affiliate. The basis difference represents the difference... false false false false false false false false false false true negated false 1 false true false false -29600000 -29.6 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Amount of amortization of the basis difference in investment in affiliate. The basis difference represents the difference between the fair value of our investment in affiliate less our share of the affiliate's equity because the affiliate's assets and liabilities retained their historical carrying value. No authoritative reference available. false 15 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 false true false false 4300000 4.3 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 16 UNE 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosureinvestmentsdetails2 false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 10 USD true false false false UNE us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_UNEMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 11 USD true false false false UNE us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_UNEMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 12 USD true false false false UNE us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_UNEMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 17 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 20 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 false true false false -24700000 -24.7 false false false 2 false true false false -5900000 -5.9 false false false 3 false true false false 1900000 1.9 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 21 Shipping JV 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosureinvestmentsdetails2 false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 13 USD true false false false Shipping JV us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_ShippingJVMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 14 USD true false false false Shipping JV us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_ShippingJVMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 15 USD true false false false Shipping JV us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_ShippingJVMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 22 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 25 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 false true false false -1800000 -1.8 false false false 2 false true false false 37400000 37.4 false false false 3 false true false false -600000 -0.6 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 26 Qualifying facilities and domestic 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosureinvestmentsdetails2 false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 16 USD true false false false Qualifying facilities and domestic us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_QualifyingFacilitiesAndDomesticPowerProjectsMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 17 USD true false false false Qualifying facilities and domestic us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_QualifyingFacilitiesAndDomesticPowerProjectsMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 18 USD true false false false Qualifying facilities and domestic us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis xbrldi http://xbrl.org/2006/xbrldi ceg_QualifyingFacilitiesAndDomesticPowerProjectsMember us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 27 Equity in earnings of investments accounted for under the equity method of accounting 2 us-gaap_ScheduleOfEquityMethodInvestmentsLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. false 30 Equity investment earnings 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false positivelabel false 1 true true false false 20700000 20.7 false false false 2 true true false false 37200000 37.2 false false false 3 true true false false 700000 0.7 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 3 20 false HundredThousands UnKnown UnKnown false true