v2.4.1.9

Significant Transactions (Narrative) (Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2013 | Dec. 31, 2014 | Mar. 19, 2013
Significant Transactions [Line Items] |  |  |
Purchase of NBCUniversal noncontrolling interest | $ 16,700,000,000 cmcsa_ConsiderationTransferredToAcquireAdditionalInterestInSubsidiaries |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 725,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource |  |
Remaining equity interest acquired |  |  | 49.00%cmcsa_NoncontrollingInterestAcquired
Company Shares Exchanged For Each Acquiree Share |  | 2.875 cmcsa_CompanySharesExchangedForEachAcquireeShare |
NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Purchase of NBCUniversal noncontrolling interest | 16,700,000,000 cmcsa_ConsiderationTransferredToAcquireAdditionalInterestInSubsidiaries / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 725,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Remaining equity interest acquired |  |  | 49.00%cmcsa_NoncontrollingInterestAcquired / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Redemption percentage | 15.00%cmcsa_RedemptionPercentage / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Comcast Corporation [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Ownership percentage in NBCUniversal Holdings | 96.00%cmcsa_OwnershipPercentage / us-gaap_BusinessAcquisitionAxis = cmcsa_ComcastCorporationMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Comcast Cash On Hand |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 11,400,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_CashMember |  |
Comcast Cash On Hand | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 11,400,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_CashMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
NBCUniversal Cash On Hand [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Portion Of Consideration Transferred Funded By NBCUniversal | 4,600,000,000 cmcsa_PortionOfConsiderationTransferredFundedByNbcuniversal / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalCashOnHandMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
NBCUniversal Enterprise Senior Unsecured Debt Securities [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 4,000,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_SeniorNotesMember |  |
NBCUniversal Enterprise Senior Unsecured Debt Securities [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 4,000,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_SeniorNotesMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Commercial Paper Program |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 750,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_CommercialPaperMember |  |
Commercial Paper Program | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 750,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = us-gaap_CommercialPaperMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Nbcuniversal Holdings Preferred Stock [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Preferred stock dividend rate percentage | 8.25%us-gaap_PreferredStockDividendRatePercentage / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalHoldingsPreferredStockMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Preferred stock liquidition preference value | 9,400,000,000 us-gaap_PreferredStockLiquidationPreferenceValue / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalHoldingsPreferredStockMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Preferred stock dividend reset rate percentage description | On March 1, 2018, and thereafter on every fifth anniversary of such date, this rate will reset to 7.44% plus the yield on actively traded United States Treasury securities having a 5 year maturity. |  |
Thirty Rockefeller Plaza And Englewood Cliffs [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Payments related to acquisition of real estate properties | 1,400,000,000 cmcsa_PaymentsRelatedToAcquisitionOfBuildings / us-gaap_BusinessAcquisitionAxis = cmcsa_ThirtyRockefellerPlazaAndEnglewoodCliffsMember |  |
Thirty Rockefeller Plaza And Englewood Cliffs [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Payments related to acquisition of real estate properties | 1,400,000,000 cmcsa_PaymentsRelatedToAcquisitionOfBuildings / us-gaap_BusinessAcquisitionAxis = cmcsa_ThirtyRockefellerPlazaAndEnglewoodCliffsMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
NBCUniversal Enterprise [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Preferred stock dividend rate percentage | 5.25%us-gaap_PreferredStockDividendRatePercentage / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseMember |  |
Fair value of redeemable preferred stock | 741,000,000 cmcsa_FairValueAmountOfRedeemablePreferredStock / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseMember | 751,000,000 cmcsa_FairValueAmountOfRedeemablePreferredStock / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseMember |
NBCUniversal Enterprise [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Ownership percentage in NBCUniversal Holdings | 4.00%cmcsa_OwnershipPercentage / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |
Merger Agreement Undertaking Number Of Divested Customers [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Number of customers |  | 3,000,000 cmcsa_NumberOfCustomers / us-gaap_BusinessAcquisitionAxis = cmcsa_MergerAgreementUndertakingNumberOfDivestedCustomersMember |
Comcast Corporate Shareholders [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Ownership Percentage In SpinCo |  | 67.00%cmcsa_OwnershipPercentageInSpinco / us-gaap_BusinessAcquisitionAxis = cmcsa_ComcastCorporateShareholdersMember |
New Charter [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Ownership Percentage In SpinCo |  | 33.00%cmcsa_OwnershipPercentageInSpinco / us-gaap_BusinessAcquisitionAxis = cmcsa_NewCharterMember |
Transaction-Related Expenses [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Other operating and administrative expenses |  | 237,000,000 cmcsa_Transactioncostsandtransactionrelatedcostsinoperatingcostsandexpenses / us-gaap_BusinessAcquisitionAxis = cmcsa_TransactionRelatedExpensesMember |
NBCUniversal Enterprise Credit Facility [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | 1,250,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseCreditFacilityMember |  |
NBCUniversal Enterprise Credit Facility [Member] | NBCUniversal Media, LLC [Member] |  |  |
Significant Transactions [Line Items] |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties | $ 1,250,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / us-gaap_BusinessAcquisitionAxis = cmcsa_NbcuniversalEnterpriseCreditFacilityMember / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember |  |

X
- Definition Represents the amount of the Company's Class A common stock that Time Warner Cable stockholders will receive in exchange for each share of Time Warner Cable common stock owned immediately prior to the merger. + References No definition available. + Details
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- Definition The consideration associated with the purchase of GE's 49% noncontrolling common equity interest in NBCUniversal related to the Redemption Transaction and the acquisition of certain properties at 30 Rockefeller Plaza and Engelwood Cliffs. + References No definition available. + Details
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- Definition The total consideration associated with the purchase of GE's 49% noncontrolling common equity interest in NBCUniversal. + References No definition available. + Details
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- Definition Fair value of our redeemable subsidiary preferred stock. + References No definition available. + Details
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- Definition Represents the percentage of voting interest acquired at the acquisition date from a noncontrolling interest. + References No definition available. + Details
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- Definition Represents the ownership percentage in NBCUniversal Holdings. + References No definition available. + Details
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- Definition The total purchase price for acquisitions of real estate properties. + References No definition available. + Details
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- Definition Portion of consideration transferred related to the Redemption Transaction and purchase of certain properties funded by NBCUniversal. + References No definition available. + Details
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- Definition The description of the percentage rate used to calculate dividend payments on preferred stock at the future reset date. + References No definition available. + Details
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- Definition The percentage of preferred units that NBCUniversal Enterprise owns for which NBCUniversal Enterprise has the right to cause NBCUniversal Holdings to redeem at a future date. + References No definition available. + Details
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- Details
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- Definition Transaction costs and transaction related costs in other operating costs and administrative expenses + References No definition available. + Details
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- Definition Value of the difference between preference in liquidation and the par or stated values of the preferred shares. + References No definition available. + Details
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