Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cable distribution system	$ 32,586	$ 31,655
Customer premise equipment	28,559	27,086
Other equipment	8,539	7,860
Buildings and leasehold improvements	10,829	8,650
Land	1,252	1,112
Property, Plant and Equipment, Gross, Total	81,765	76,363
Less: Accumulated depreciation	48,100	45,410
Property and equipment, net	33,665	30,953
NBCUniversal Media LLC [Member]
Buildings and leasehold improvements	6,543	5,780
Land	961	820
Furniture, fixtures and equipment	3,457	2,930
Construction in process	1,339	775
Property, Plant and Equipment, Gross, Total	12,300	10,305
Less: Accumulated depreciation	2,779	2,167
Property and equipment, net	$ 9,521	$ 8,138
Cable Distribution System [Member]
Weighted average original useful life (in years)	11 years
Customer Premise Equipment [Member]
Weighted average original useful life (in years)	6 years
Other Equipment [Member]
Weighted average original useful life (in years)	7 years
Buildings and Leasehold Improvements [Member]
Weighted average original useful life (in years)	25 years
Buildings and Leasehold Improvements [Member] \| NBCUniversal Media LLC [Member]
Weighted average original useful life (in years)	27 years
Machinery And Equipment [Member] \| NBCUniversal Media LLC [Member]
Weighted average original useful life (in years)	9 years
Comcast Center [Member]
Equity interest acquired			80.00%

Costs associated with the construction of and improvements to our cable transmission and distribution facilities.

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The cost of customer premises equipment.

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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