Name:	exc_GainLossInvestmentIncomeNuclearDecommissioningTrustFunds
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Gain / loss on nuclear decommissioning trust fund investments abstract.

No definition available.

Name:	exc_GainLossOnNuclearDecommissioningTrustFundInvestmentsAbstract
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This item represents investment income and realized gains (losses) for the period as a result of selling marketable securities held in nuclear decommissioning trust funds classified as trading securities.

No definition available.

Name:	exc_RealizedGainLossInvestmentIncomeNuclearDecommissioningTrustFundsNonregulatoryAccounting
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This item represents investment income and realized gains (losses) for the period as a result of selling marketable securities held in nuclear decommissioning trust funds and classified as trading securities. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement.

No definition available.

Name:	exc_RealizedGainLossInvestmentIncomeNuclearDecommissioningTrustFundsRegulatoryAccounting
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This item represents the contractual elimination of nuclear decommissioning trust fund-related activity, which may include realized income (losses), unrealized income (losses), asset retirement obligation accretion, asset retirement cost amortization, investment income and related income taxes. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement.

No definition available.

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This item represents unrealized gains (losses) included in earnings for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities.

No definition available.

Name:	exc_UnrealizedGainLossNuclearDecommissioningTrustFundsNonregulatoryAccounting
Namespace Prefix:	exc_
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This item represents unrealized gains (losses) for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement.

No definition available.

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Namespace Prefix:	exc_
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Period Type:	duration

Amount of net periodic benefit cost (credit) for defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
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-Publisher FASB
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The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 835
-Section 45
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