2.2.0.7 true Stock Based Compensation (Details) (USD $) 4140 - Disclosure - Stock Based Compensation (Details) true false In Millions, except Share data, unless otherwise specified 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 $ false 2 USD true false false false us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis explicitMember 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 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD true false false false us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis explicitMember USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 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 $ false 4 USD true false false false us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_EmployeeStockOptionMember us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis explicitMember USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 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 $ 4 Stock Based Compensation 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems 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 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true 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 5 Number of shares authorized for issuance under 2007 Long-Term Incentive Plan 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized us-gaap true na instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 9000000 9000000 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:sharesItemType shares The maximum number of shares originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the share-based compensation plan. As stock options and equity instruments other than options are awarded to participants, the shares remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph a false 6 Number of shares available for issuance under the 2007 Long-Term Incentive Plan 3 us-gaap_CommonStockCapitalSharesReservedForFutureIssuance us-gaap true na instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 5790545 5790545 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:sharesItemType shares Aggregate number of common shares reserved for future issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 false 7 Maximum vesting period for non-qualified stock options (in years) 3 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximumYears ceg false na duration The maximum period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 3 3 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:integerItemType integer The maximum period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in years. No authoritative reference available. false 8 Expiration of non-qualified stock options from date of grant (in years) 3 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDateYears ceg false na duration The expiration date of non-qualified stock options from the date of grant, in years. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 10 10 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:integerItemType integer The expiration date of non-qualified stock options from the date of grant, in years. No authoritative reference available. false 9 Weighted- average assumptions for Black-Scholes option pricing model 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract 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 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 10 Risk-free interest rate (in hundredths) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 0.0195 0.0195 true false false 3 false true false false 0.0257 0.0257 true false false 4 false true false false 0.0469 0.0469 true false false us-types:percentItemType pure The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(d) false 11 Expected life (in years) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 4 4 true false false 3 false true false false 4 4 true false false 4 false true false false 4 4 true false false xbrli:decimalItemType decimal The period of time a share-based award is expected to be outstanding. A share-based award's expected term shall be determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior. An entity is required to aggregate individual awards into relatively homogeneous groups. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section D -Subsection 2 false 12 Expected market price volatility factor (in hundredths) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 0.378 0.378 true false false 3 false true false false 0.258 0.258 true false false 4 false true false false 0.203 0.203 true false false us-types:percentItemType pure The estimated measure of the percentage amount by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(b) false 13 Expected dividend yield (in hundredths) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 0.0483 0.0483 true false false 3 false true false false 0.0185 0.0185 true false false 4 false true false false 0.025 0.025 true false false us-types:percentItemType pure The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(c) false 14 Changes in stock option grants, shares 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward 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 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:stringItemType string A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. false 15 Outstanding, beginning of year 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel false 1 false false false false 0 0 false false false 2 false true false false 6058000 6058000 true false false 3 false true false false 6145000 6145000 true false false 4 false true false false 6051000 6051000 true false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(b) false 16 Granted with exercise prices at fair market value 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 3511000 3511000 true false false 3 false true false false 1434000 1434000 true false false 4 false true false false 1759000 1759000 true false false xbrli:sharesItemType shares The quantity of shares issuable on stock options awarded under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(d) false 17 Exercised 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriod us-gaap true na duration No definition available. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -83000 -83000 true false false 3 false true false false -375000 -375000 true false false 4 false true false false -1411000 -1411000 true false false xbrli:sharesItemType shares The decrease in the number of reserved shares that could potentially be issued attributable to the exercise or conversion during the reporting period of previously issued stock options under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(e) false 18 Forfeited/expired 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -1340000 -1340000 true false false 3 false true false false -1146000 -1146000 true false false 4 false true false false -254000 -254000 true false false xbrli:sharesItemType shares For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired. No authoritative reference available. false 19 Outstanding, end of year 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel false 1 false false false false 0 0 false false false 2 false true false false 8146000 8146000 true false false 3 false true false false 6058000 6058000 true false false 4 false true false false 6145000 6145000 true false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(b) false 20 Exercisable, end of year (in shares) 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber us-gaap true na instant No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 4114000 4114000 true false false 3 false true false false 4665000 4665000 true false false 4 false true false false 4043000 4043000 true false false xbrli:sharesItemType shares The number of shares into which fully or partially vested stock options outstanding as of the balance-sheet date can be currently converted under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(c), d(2) false 21 Changes in stock option grants, weighted average exercise price 3 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollForward ceg false 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 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 22 Outstanding, beginning of year (in dollars per share) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 59.99 59.99 true false false 3 true true false false 55.90 55.90 true false false 4 true true false false 47.23 47.23 true false false us-types:perShareItemType decimal The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) false 23 Granted with exercise prices at fair market value (in dollars per share) 4 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValuePerShare ceg false na duration The weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded under the... false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 20.14 20.14 true false false 3 true true false false 93.79 93.79 true false false 4 true true false false 76.22 76.22 true false false us-types:perShareItemType decimal The weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period. No authoritative reference available. false 24 Exercised (in dollars per share) 4 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesDuringPeriodWeightedAverageExercisePrice ceg false na duration The weighted average price at which option holders acquired shares when converting their stock options into shares under the... false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 31.07 31.07 true false false 3 true true false false 47.02 47.02 true false false 4 true true false false 41.91 41.91 true false false us-types:perShareItemType decimal The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period. No authoritative reference available. false 25 Forfeited/expired (in dollars per share) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 52.41 52.41 true false false 3 true true false false 84.59 84.59 true false false 4 true true false false 67.85 67.85 true false false us-types:perShareItemType decimal For presentations that combine terminations, the weighted average price of expired options and the price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period . No authoritative reference available. false 26 Outstanding, end of year (in dollars per share) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel true 1 false false false false 0 0 false false false 2 true true false false 44.36 44.36 true false false 3 true true false false 59.99 59.99 true false false 4 true true false false 55.90 55.90 true false false us-types:perShareItemType decimal The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) false 27 Exercisable, end of year (in dollars per share) 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 55.81 55.81 true false false 3 true true false false 52.13 52.13 true false false 4 true true false false 48.51 48.51 true false false us-types:perShareItemType decimal The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(c) false 28 Weighted average fair value per share of options granted with exercise prices at fair market value (in dollars per share) 3 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 4.24 4.24 true false false 3 true true false false 18.75 18.75 true false false 4 true true false false 13.76 13.76 true false false us-types:perShareItemType decimal The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) false 29 Additional information about stock options 3 ceg_StockOptionsExercisedAbstract ceg false 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 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 30 Stock Option Expense Recognized 4 us-gaap_AllocatedShareBasedCompensationExpense us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 true true false false 14200000 14.2 true false false 3 true true false false 11000000 11.0 true false false 4 true true false false 15100000 15.1 true false false xbrli:monetaryItemType monetary Represents the expense recognized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph 64 -Subparagraph b Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph g(1) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F false 31 Cash Received for Exercise Price (in dollars) 4 us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 2600000 2.6 true false false 3 false true false false 20200000 20.2 true false false 4 false true false false 43400000 43.4 true false false xbrli:monetaryItemType monetary Aggregate proceeds received by the entity during the annual period from exercises of stock options and conversion of similar instruments granted under share-based payment arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph i false 32 Intrinsic Value Realized by Employee (in dollars) 4 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 200000 0.2 true false false 3 false true false false 14100000 14.1 true false false 4 false true false false 67600000 67.6 true false false xbrli:monetaryItemType monetary The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(2) false 33 Realized Tax Benefit (in dollars) 4 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense us-gaap true credit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 100000 0.1 true false false 3 false true false false 5700000 5.7 true false false 4 false true false false 26700000 26.7 true false false xbrli:monetaryItemType monetary The total recognized tax benefit related to compensation cost for share-based payment arrangements recognized in income during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph g(1) false 34 Fair Value of Options that Vested (in dollars) 4 ceg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriodTotalFairValue ceg false debit duration The total fair value of options for which the grantee gained the right during the reporting period, by satisfying service and... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 11000000 11.0 true false false 3 false true false false 98300000 98.3 true false false 4 false true false false 82700000 82.7 true false false xbrli:monetaryItemType monetary The total fair value of options for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. No authoritative reference available. false 35 Unrecognized compensation cost related to the unvested portion of outstanding stock option awards (in dollars) 4 us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized us-gaap true debit instant No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 4000000 4.0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:monetaryItemType monetary As of the balance-sheet date, the aggregate unrecognized cost of share-based awards made to employees under share-based compensation plans that have yet to vest. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph h false 36 Compensation cost related to the unvested portion of outstanding stock option awards expected to be recognized in next year (in dollars) 4 ceg_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationExpectedToBeRecognizedInSubsequentYear ceg false debit instant This element represents the portion of the aggregate unrecognized cost of share-based awards made to employees under... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 true true false false 2900000 2.9 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false xbrli:monetaryItemType monetary This element represents the portion of the aggregate unrecognized cost of share-based awards made to employees under share-based compensation plans that have yet to vest, that is expected to be recognized in the next year. No authoritative reference available. false 4 33 false HundredThousands NoRounding UnKnown true true