Name:	ceg_AmountOfVotesForAllSharesOfPreferenceStockOutstandingRequiredToAmendCharterAffectingShares
Namespace Prefix:	ceg_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

This element represents the required equity ratio after dividend payments, as calculated pursuant to the Maryland PSC's ratemaking precedents, minimum.

No definition available.

Name:	ceg_EquityRatioAfterDividendPaymentMinimum
Namespace Prefix:	ceg_
Data Type:	num:percentItemType
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Period Type:	instant

The major external credit rating agencies, number.

No definition available.

Name:	ceg_MajorExternalCreditRatingAgenciesNumber
Namespace Prefix:	ceg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the number of votes per share of preference stock on any charter amendment.

No definition available.

Name:	ceg_NumberOfVotesPerShareOfPreferenceStockOnCharterAmendment
Namespace Prefix:	ceg_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Represents the number of votes per share of preference stock available to preference stockholders when entity fails to pay full dividends on the preference stock and such failure continues for one year.

No definition available.

Name:	ceg_NumberOfVotesPerShareOfPreferenceStockOnFailureOfDividendPayments
Namespace Prefix:	ceg_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

Represents the period over which the entity fails to pay the full dividend on shares of preference stock.

No definition available.

Name:	ceg_PreferenceStockFailureOfDividendPaymentPeriod
Namespace Prefix:	ceg_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

This element represents the number of major credit rating agencies that would have to rate BGE's senior unsecured credit rating below investment grade for there to be a dividend payment restriction.

No definition available.

Name:	ceg_RequiredMajorCreditRatingAgenciesToRateBelowInvestmentGradeForDividendPaymentRestrictions
Namespace Prefix:	ceg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the term of debt instrument.

No definition available.

Name:	ceg_TermOfDebtInstrument
Namespace Prefix:	ceg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the term of fixed rate note.

No definition available.

Name:	ceg_TermOfFixedRateNote
Namespace Prefix:	ceg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ceg_WeightedAverageInterestRatesForVariableRateDebtAbstract
Namespace Prefix:	ceg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The average effective interest rate during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
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Period Type:	duration

- Details

Name:	us-gaap_DisclosureOfRestrictionsOnDividendsLoansAndAdvancesDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of long-term debt maturities after year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of long-term debt maturing within the next twelve months following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
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Amount of long-term debt maturing in year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
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Period Type:	instant

Amount of long-term debt maturing in year four following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
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Period Type:	instant

Amount of long-term debt maturing in year three following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of long-term debt maturing in year two following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_MaturitiesOfLongTermDebtAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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Aggregate notional amount of interest rate derivatives, which relates to the currency amount specified in the interest rate derivative instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959