Financial Data by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Revenue	$ 18,790	$ 17,853
Operating income (loss) before depreciation and amortization	6,367	5,956
Depreciation and amortization	2,278	2,066
Operating income (loss)	4,089	3,890
Capital expenditures	1,885	1,726
NBCUniversal Media LLC [Member]
Revenue	6,861	6,604
Operating income (loss) before depreciation and amortization	1,622	1,494
Depreciation and amortization	414	364
Operating income (loss)	1,208	1,130
Capital expenditures	295	268
Cable Communications [Member]
Revenue	12,204	11,441
Operating income (loss) before depreciation and amortization	4,889	4,658
Depreciation and amortization	1,843	1,680
Operating income (loss)	3,046	2,978
Capital expenditures	$ 1,576	$ 1,446
Cable segment revenue types as percentage of total cable revenue	100.00%	100.00%
Cable Networks [Member]
Revenue	$ 2,453	$ 2,359
Operating income (loss) before depreciation and amortization	956	898
Depreciation and amortization	190	184
Operating income (loss)	766	714
Capital expenditures	1	6
Cable Networks [Member] \| NBCUniversal Media LLC [Member]
Revenue	2,453	2,359
Operating income (loss) before depreciation and amortization	956	898
Depreciation and amortization	190	184
Operating income (loss)	766	714
Capital expenditures	1	6
Broadcast Television [Member]
Revenue	2,084	2,248
Operating income (loss) before depreciation and amortization	284	182
Depreciation and amortization	32	29
Operating income (loss)	252	153
Capital expenditures	19	11
Broadcast Television [Member] \| NBCUniversal Media LLC [Member]
Revenue	2,084	2,248
Operating income (loss) before depreciation and amortization	284	182
Depreciation and amortization	32	29
Operating income (loss)	252	153
Capital expenditures	19	11
Filmed Entertainment [Member]
Revenue	1,383	1,446
Operating income (loss) before depreciation and amortization	167	293
Depreciation and amortization	8	5
Operating income (loss)	159	288
Capital expenditures	3	1
Filmed Entertainment [Member] \| NBCUniversal Media LLC [Member]
Revenue	1,383	1,446
Operating income (loss) before depreciation and amortization	167	293
Depreciation and amortization	8	5
Operating income (loss)	159	288
Capital expenditures	3	1
Theme Parks [Member]
Revenue	1,026	651
Operating income (loss) before depreciation and amortization	375	244
Depreciation and amortization	98	66
Operating income (loss)	277	178
Capital expenditures	200	162
Theme Parks [Member] \| NBCUniversal Media LLC [Member]
Revenue	1,026	651
Operating income (loss) before depreciation and amortization	375	244
Depreciation and amortization	98	66
Operating income (loss)	277	178
Capital expenditures	200	162
Headquarters And Other [Member]
Revenue	3	4
Operating income (loss) before depreciation and amortization	(160)	(140)
Depreciation and amortization	86	80
Operating income (loss)	(246)	(220)
Capital expenditures	72	88
Headquarters And Other [Member] \| NBCUniversal Media LLC [Member]
Revenue	3	4
Operating income (loss) before depreciation and amortization	(160)	(140)
Depreciation and amortization	86	80
Operating income (loss)	(246)	(220)
Capital expenditures	72	88
NBCUniversal Eliminations [Member]
Revenue	(88)	(104)
Operating income (loss) before depreciation and amortization	0	(2)
Depreciation and amortization	0	0
Operating income (loss)	0	(2)
Capital expenditures	0	0
NBCUniversal Eliminations [Member] \| NBCUniversal Media LLC [Member]
Revenue	(88)	(104)
Operating income (loss) before depreciation and amortization	0	17
Depreciation and amortization	0	0
Operating income (loss)	0	17
Capital expenditures	0	0
NBCUniversal [Member]
Revenue	6,861	6,604
Operating income (loss) before depreciation and amortization	1,622	1,475
Depreciation and amortization	414	364
Operating income (loss)	1,208	1,111
Capital expenditures	295	268
Corporate and Other [Member]
Revenue	199	193
Operating income (loss) before depreciation and amortization	(154)	(209)
Depreciation and amortization	21	22
Operating income (loss)	(175)	(231)
Capital expenditures	14	12
Eliminations [Member]
Revenue	(474)	(385)
Operating income (loss) before depreciation and amortization	10	32
Depreciation and amortization	0	0
Operating income (loss)	10	32
Capital expenditures	$ 0	$ 0
Cable Communications Segment Revenue Percentage-Video [Member]
Cable segment revenue types as percentage of total cable revenue	45.40%	46.60%
Cable Communications Segment Revenue Percentage - High-speed Internet [Member]
Cable segment revenue types as percentage of total cable revenue	26.80%	26.60%
Cable Communications Segment Revenue Percentage- Voice [Member]
Cable segment revenue types as percentage of total cable revenue	7.30%	7.90%
Cable Communications Segment Revenue Percentage- Business Services [Member]
Cable segment revenue types as percentage of total cable revenue	10.70%	9.80%
Cable Communications Segment Revenue Percentage- Advertising [Member]
Cable segment revenue types as percentage of total cable revenue	4.60%	4.40%
Cable Communications Segment Revenue Percentage- Other [Member]
Cable segment revenue types as percentage of total cable revenue	5.20%	4.70%
Cable Communications Segment Revenue Percentage- Franchise and other regulatory fees [Member]
Cable segment revenue types as percentage of total cable revenue	2.90%	2.80%

Cable segment revenue types as percentage of total cable revenue

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- Definition

This element represents the operating income or loss excluding depreciation and amortization.

+ References

No definition available.

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The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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The net result for the period of deducting operating expenses from operating revenues.

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- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB
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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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