v2.4.1.9

Long-Term Debt (Narrative) (Details) (USD $) | 3 Months Ended
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Mar. 31, 2015
Total debt | $ 47,100,000,000 us-gaap_DebtAndCapitalLeaseObligations
Long-term Debt, Fair Value | 54,900,000,000 us-gaap_LongTermDebtFairValue
Amounts available under revolving credit facilities | 6,600,000,000 us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
NBCUniversal Media, LLC [Member] |
Total debt | 10,200,000,000 us-gaap_DebtAndCapitalLeaseObligations / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember
Long-term Debt, Fair Value | 11,600,000,000 us-gaap_LongTermDebtFairValue / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember
Comcast ownership in cable holding company subsidiaries | 100.00%cmcsa_ComcastOwnershipInCableHoldingCompanySubsidiaries / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember
NBCUniversal Enterprise [Member] |
Commercial paper | 700,000,000 us-gaap_CommercialPaper / dei_LegalEntityAxis = cmcsa_NbcuniversalEnterpriseMember
NBCUniversal Enterprise [Member] | NBCUniversal Media, LLC [Member] |
Principal amount | 4,000,000,000 us-gaap_DebtInstrumentFaceAmount / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_NbcuniversalEnterpriseMember
Preferred stock liquidation preference value | 725,000,000 us-gaap_PreferredStockLiquidationPreferenceValue / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_NbcuniversalEnterpriseMember
Guarantee Obligations Current Principal Balance | 1,350,000,000 cmcsa_GuaranteeObligationsCurrentPrincipalBalance / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_NbcuniversalEnterpriseMember
Comcast And Comcast Cable Revolving Credit Facility [Member] | NBCUniversal Media, LLC [Member] |
Debt Instrument, Maturity Date, Description | 2017
Revolver Line of credit amount outstanding | 0 us-gaap_LineOfCredit / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_ComcastAndComcastCableRevolvingCreditFacilityMember
Guarantee Obligations Current Principal Balance | 6,250,000,000 cmcsa_GuaranteeObligationsCurrentPrincipalBalance / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_ComcastAndComcastCableRevolvingCreditFacilityMember
Comcast And Comcast Cable Debt Securities [Member] | NBCUniversal Media, LLC [Member] |
Guarantee Obligations Current Principal Balance | 31,700,000,000 cmcsa_GuaranteeObligationsCurrentPrincipalBalance / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember / dei_LegalEntityAxis = cmcsa_ComcastAndComcastCableDebtSecuritiesMember
NBCUniversal Enterprise Credit Facility [Member] |
Amounts available under revolving credit facilities | $ 650,000,000 us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / dei_LegalEntityAxis = cmcsa_NbcuniversalEnterpriseCreditFacilityMember

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- Definition Represents the Company's ownership in its cable holding company subsidiaries. + References No definition available. + Details
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Balance Type: | na
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- Definition Principal amount of debt securities subject to guarantee. + References No definition available. + Details
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- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(2)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Subparagraph a(3) -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 13 -Subparagraph 2 -Article 9 + Details
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- Definition Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13,16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
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- Definition Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities. + References 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 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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Balance Type: | credit
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- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References 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 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + 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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