v2.4.0.6

Supplemental Financial Information (Operating Costs and Expenses (Excluding Depreciation and Amortization))(Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2012 | Jun. 30, 2011 | Jun. 30, 2012 | Jun. 30, 2011
Supplemental Financial Information [Abstract] |  |  |  |
Programming and production | $ 4,554 | $ 4,323 | $ 9,290 | $ 7,593
Cable Communications technical labor | 579 | 568 | 1,167 | 1,161
Cable Communications customer service | 481 | 460 | 975 | 929
Advertising, marketing and promotion | 1,287 | 1,105 | 2,489 | 2,075
Other | 3,306 | 3,076 | 6,476 | 5,836
Operating costs and expenses (excluding depreciation and amortization) | $ 10,207 | $ 9,532 | $ 20,397 | $ 17,594

X
- Definition Cable Communications customer service + References No definition available. + Details
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Namespace Prefix: | cmcsa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cable Communications Technical Labor + References No definition available. + Details
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Namespace Prefix: | cmcsa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating costs and expenses including amortization of film and television costs but excluding intangible amortization and depreciation. + References No definition available. + Details
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Namespace Prefix: | cmcsa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Other Operating Costs And Expenses + References No definition available. + Details
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Namespace Prefix: | cmcsa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Programming and Production Costs + References No definition available. + Details
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Namespace Prefix: | cmcsa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | cmcsa_SupplementalFinancialInformationAbstract
Namespace Prefix: | cmcsa_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The total expense recognized in the period for promotion, public relations, and brand or product advertising. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration