v2.4.0.8

Share-Based Compensation (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Stock Options [Member]
Unrecognized pretax compensation expense on nonvested awards	$ 318
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)	1 year 10 months 24 days
Stock Options [Member] | NBCUniversal Media, LLC [Member]
Unrecognized pretax compensation expense on nonvested awards	35
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)	2 years 2 months 12 days
Restricted Share Units [Member]
Unrecognized pretax compensation expense on nonvested awards	380
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)	1 year 8 months 12 days
Restricted Share Units [Member] | NBCUniversal Media, LLC [Member]
Unrecognized pretax compensation expense on nonvested awards	$ 98
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)	1 year 8 months 12 days

X

- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration