v2.4.1.9

Supplemental Financial Information (Noncash Investing and Financing Activities)(Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Mar. 19, 2013
Noncontrolling Interest Acquired |  |  |  | 49.00%cmcsa_NoncontrollingInterestAcquired
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 |  |
Total noncash consideration transferred related to the Redemption Transaction |  | 6,000,000,000 cmcsa_TotalNoncashConsiderationTransferredInRedemptionTransaction |  |
Dividends payable, amount | 572,000,000 us-gaap_DividendsPayableCurrentAndNoncurrent | 509,000,000 us-gaap_DividendsPayableCurrentAndNoncurrent | 430,000,000 us-gaap_DividendsPayableCurrentAndNoncurrent |
Dividends payable, amount per share | $ 0.225 us-gaap_DividendsPayableAmountPerShare | $ 0.195 us-gaap_DividendsPayableAmountPerShare | $ 0.1625 us-gaap_DividendsPayableAmountPerShare |
Capital expenditures incurred but not yet paid | 797,000,000 us-gaap_CapitalExpendituresIncurredButNotYetPaid | 872,000,000 us-gaap_CapitalExpendituresIncurredButNotYetPaid | 757,000,000 us-gaap_CapitalExpendituresIncurredButNotYetPaid |
Noncash or Part Noncash Acquisition, Fixed Assets Acquired |  |  | 85,000,000 us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1 |
Fair Value Equity Securities Settlement | 3,200,000,000 cmcsa_FairValueEquitySecuritiesSettlement | 1,400,000,000 cmcsa_FairValueEquitySecuritiesSettlement |  |
NBCUniversal Media, LLC [Member] |  |  |  |
Capital expenditures incurred but not yet paid | 148,000,000 us-gaap_CapitalExpendituresIncurredButNotYetPaid / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember | 306,000,000 us-gaap_CapitalExpendituresIncurredButNotYetPaid / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember |  |
Noncash or Part Noncash Acquisition, Fixed Assets Acquired |  |  | 85,000,000 us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1 / cmcsa_LegalEntity1Axis = cmcsa_NBCUniversalMediaLLCMember |
Revolving Credit Facility Member |  |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties |  | 1,250,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / dei_LegalEntityAxis = us-gaap_RevolvingCreditFacilityMember |  |
NBCUniversal Enterprise Senior Unsecured Debt Securities [Member] |  |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties |  | 4,000,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / dei_LegalEntityAxis = us-gaap_SeniorNotesMember |  |
NBCUniversal Enterprise Preferred Stock [Member] |  |  |  |
Consideration transferred related to the Redemption Transaction and purchase of certain properties |  | $ 725,000,000 cmcsa_ConsiderationTransferredRelatedToRedemptionTransactionByFundingSource / dei_LegalEntityAxis = us-gaap_PreferredStockMember |  |

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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 method equity securities used to settle our obligations under prepaid forward sale agreements in the period. + 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 Future cash outflow to pay for purchases of fixed assets that have occurred. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
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- Definition The per share amount of a dividend declared, but not paid, as of the financial reporting date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
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- Definition Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding. + 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 210.9-03.15(5)) -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 03 -Paragraph 15 -Subparagraph a -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph 5 -Article 9 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15(5)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition The amount of fixed assets that an Entity acquires in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
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