Long-Term Debt (Narrative) (Details) $ in Millions	9 Months Ended
Sep. 30, 2015 USD ($)
Total debt	$ 47,800
Long-term Debt, Fair Value	53,200
Amounts available under revolving credit facilities	6,700
NBCUniversal Media, LLC [Member]
Total debt	9,300
Long-term Debt, Fair Value	$ 10,200
Comcast ownership in cable holding company subsidiaries	100.00%
NBCUniversal Enterprise [Member]
Commercial paper	$ 635
NBCUniversal Enterprise [Member] \| NBCUniversal Media, LLC [Member]
Related Party Aggregate Principal Amount Senior Notes Not Subject To Guarantee	4,000
Related Party Credit Facility Not Subject To Guarantee	1,350
Related Party Liquidation Preference Preferred Stock Not Subject To Guarantee	725
NBCUniversal Enterprise Credit Facility [Member]
Amounts available under revolving credit facilities	715
Comcast And Comcast Cable Debt Securities [Member] \| NBCUniversal Media, LLC [Member]
Guarantee Obligations Current Principal Balance	$ 33,200
Comcast And Comcast Cable Communications, LLC Revolving Credit Facility [Member]
Debt Instrument, Maturity Date, Description	June 2017
Guarantee Obligations Current Principal Balance	$ 6,250
Comcast And Comcast Cable Communications, LLC Revolving Credit Facility [Member] \| NBCUniversal Media, LLC [Member]
Debt Instrument, Maturity Date, Description	June 2017
Revolver Line of credit amount outstanding	$ 0
Guarantee Obligations Current Principal Balance	$ 6,250

Represents the Company's ownership in its cable holding company subsidiaries.

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Principal amount of debt securities subject to guarantee.

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Represents the related party aggregate principal amount of senior notes not subject to guarantee by NBCUniversal.

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Represents the related party credit facility not subject to guarantee by NBCUniversal.

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Represents the related party liquidation preference of preferred stock not subject to guarantee by NBCUniversal.

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No definition available.

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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 FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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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.

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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.

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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.

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-Name Accounting Standards Codification

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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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

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