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Related Party Transactions (Condensed Consolidated Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Revenue	$ 26,859	$ 22,791
Total costs and expenses	(21,677)	(18,146)
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Revenue	8,345	9,530
Total costs and expenses	(6,513)	(7,755)
Comcast and Consolidated Subsidiaries [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Revenue	604	594
Total costs and expenses	(65)	(61)
Interest expense and investment and other income (loss), net	$ 8	$ (23)

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Represents the intercompany transactions with ultimate parent, which are included in interest expense and investment and other income (loss), net.

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Total costs of sales and operating expenses for the period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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