Financial Data by Business Segment (Details) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Revenue	$ 17,853,000,000us-gaap_Revenues	$ 17,408,000,000us-gaap_Revenues
Operating income (loss) before depreciation and amortization	5,956,000,000	5,538,000,000
Depreciation and amortization	2,066,000,000us-gaap_DepreciationAndAmortization	1,970,000,000us-gaap_DepreciationAndAmortization
Operating income (loss)	3,890,000,000us-gaap_OperatingIncomeLoss	3,568,000,000us-gaap_OperatingIncomeLoss
Capital expenditures	1,726,000,000	1,448,000,000
NBCUniversal Media, LLC [Member]
Revenue	6,604,000,000	6,876,000,000
Operating income (loss) before depreciation and amortization	1,494,000,000	1,311,000,000
Depreciation and amortization	364,000,000	365,000,000
Operating income (loss)	1,130,000,000	946,000,000
Capital expenditures	268,000,000	291,000,000
Cable Communications [Member]
Revenue	11,430,000,000	10,757,000,000
Operating income (loss) before depreciation and amortization	4,674,000,000	4,400,000,000
Depreciation and amortization	1,675,000,000	1,584,000,000
Operating income (loss)	2,999,000,000	2,816,000,000
Capital expenditures	1,445,000,000	1,145,000,000
Cable segment revenue types as percentage of total cable revenue	100.00%	100.00%
Cable Networks [Member]
Revenue	2,359,000,000	2,505,000,000
Operating income (loss) before depreciation and amortization	898,000,000	895,000,000
Depreciation and amortization	184,000,000	189,000,000
Operating income (loss)	714,000,000	706,000,000
Capital expenditures	6,000,000	11,000,000
Cable Networks [Member] \| NBCUniversal Media, LLC [Member]
Revenue	2,359,000,000	2,505,000,000
Operating income (loss) before depreciation and amortization	898,000,000	895,000,000
Depreciation and amortization	184,000,000	189,000,000
Operating income (loss)	714,000,000	706,000,000
Capital expenditures	6,000,000	11,000,000
Broadcast Television [Member]
Revenue	2,248,000,000	2,621,000,000
Operating income (loss) before depreciation and amortization	182,000,000	122,000,000
Depreciation and amortization	29,000,000	27,000,000
Operating income (loss)	153,000,000	95,000,000
Capital expenditures	11,000,000	11,000,000
Broadcast Television [Member] \| NBCUniversal Media, LLC [Member]
Revenue	2,248,000,000	2,621,000,000
Operating income (loss) before depreciation and amortization	182,000,000	122,000,000
Depreciation and amortization	29,000,000	27,000,000
Operating income (loss)	153,000,000	95,000,000
Capital expenditures	11,000,000	11,000,000
Filmed Entertainment [Member]
Revenue	1,446,000,000	1,351,000,000
Operating income (loss) before depreciation and amortization	293,000,000	288,000,000
Depreciation and amortization	5,000,000	5,000,000
Operating income (loss)	288,000,000	283,000,000
Capital expenditures	1,000,000	1,000,000
Filmed Entertainment [Member] \| NBCUniversal Media, LLC [Member]
Revenue	1,446,000,000	1,351,000,000
Operating income (loss) before depreciation and amortization	293,000,000	288,000,000
Depreciation and amortization	5,000,000	5,000,000
Operating income (loss)	288,000,000	283,000,000
Capital expenditures	1,000,000	1,000,000
Theme Parks [Member]
Revenue	651,000,000	487,000,000
Operating income (loss) before depreciation and amortization	263,000,000	170,000,000
Depreciation and amortization	66,000,000	69,000,000
Operating income (loss)	197,000,000	101,000,000
Capital expenditures	162,000,000	144,000,000
Theme Parks [Member] \| NBCUniversal Media, LLC [Member]
Revenue	651,000,000	487,000,000
Operating income (loss) before depreciation and amortization	263,000,000	170,000,000
Depreciation and amortization	66,000,000	69,000,000
Operating income (loss)	197,000,000	101,000,000
Capital expenditures	162,000,000	144,000,000
Headquarters And Other [Member]
Revenue	4,000,000	2,000,000
Operating income (loss) before depreciation and amortization	(140,000,000)	(163,000,000)
Depreciation and amortization	80,000,000	75,000,000
Operating income (loss)	(220,000,000)	(238,000,000)
Capital expenditures	88,000,000	124,000,000
Headquarters And Other [Member] \| NBCUniversal Media, LLC [Member]
Revenue	4,000,000	2,000,000
Operating income (loss) before depreciation and amortization	(140,000,000)	(163,000,000)
Depreciation and amortization	80,000,000	75,000,000
Operating income (loss)	(220,000,000)	(238,000,000)
Capital expenditures	88,000,000	124,000,000
NBCUniversal Eliminations [Member]
Revenue	(104,000,000)	(90,000,000)
Operating income (loss) before depreciation and amortization	(2,000,000)	(1,000,000)
Depreciation and amortization	0	0
Operating income (loss)	(2,000,000)	(1,000,000)
Capital expenditures	0	0
NBCUniversal Eliminations [Member] \| NBCUniversal Media, LLC [Member]
Revenue	(104,000,000)	(90,000,000)
Operating income (loss) before depreciation and amortization	(2,000,000)	(1,000,000)
Depreciation and amortization	0	0
Operating income (loss)	(2,000,000)	(1,000,000)
Capital expenditures	0	0
NBCUniversal [Member]
Revenue	6,604,000,000	6,876,000,000
Operating income (loss) before depreciation and amortization	1,494,000,000	1,311,000,000
Depreciation and amortization	364,000,000	365,000,000
Operating income (loss)	1,130,000,000	946,000,000
Capital expenditures	268,000,000	291,000,000
Corporate and Other [Member]
Revenue	204,000,000	174,000,000
Operating income (loss) before depreciation and amortization	(225,000,000)	(153,000,000)
Depreciation and amortization	27,000,000	21,000,000
Operating income (loss)	(252,000,000)	(174,000,000)
Capital expenditures	13,000,000	12,000,000
Eliminations [Member]
Revenue	(385,000,000)	(399,000,000)
Operating income (loss) before depreciation and amortization	13,000,000	(20,000,000)
Depreciation and amortization	0	0
Operating income (loss)	13,000,000	(20,000,000)
Capital expenditures	$ 0	$ 0
Cable Communications Segment Revenue Percentage-Video [Member]
Cable segment revenue types as percentage of total cable revenue	46.60%	48.10%
Cable Communications Segment Revenue Percentage - High-speed Internet [Member]
Cable segment revenue types as percentage of total cable revenue	26.60%	25.60%
Cable Communications Segment Revenue Percentage- Voice [Member]
Cable segment revenue types as percentage of total cable revenue	7.90%	8.50%
Cable Communications Segment Revenue Percentage- Business Services [Member]
Cable segment revenue types as percentage of total cable revenue	9.70%	8.50%
Cable Communications Segment Revenue Percentage- Advertising [Member]
Cable segment revenue types as percentage of total cable revenue	4.40%	4.70%
Cable Communications Segment Revenue Percentage- Other [Member]
Cable segment revenue types as percentage of total cable revenue	4.80%	4.60%
Cable Communications Segment Revenue Percentage- Franchise and other regulatory fees [Member]
Cable segment revenue types as percentage of total cable revenue	2.80%	2.80%

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

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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.

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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.

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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).

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