Segment Information (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment			6
Financial Data by Business Segment
Revenue	$ 26,858	$ 21,735	$ 53,717	$ 44,526
Adjusted EBITDA	8,716	7,417	17,269	14,661
Depreciation and Amortization	3,276	2,603	6,596	5,202
Capital Expenditures	2,263	2,250	4,355	4,223
Cash Paid for Intangible Assets	531	511	$ 1,078	930
NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Number of reportable segments \| segment			4
Financial Data by Business Segment
Revenue	8,227	8,313	$ 16,572	17,843
Adjusted EBITDA	2,311	2,160	4,658	4,445
Depreciation and Amortization	527	553	1,042	1,063
Capital Expenditures	473	461	926	730
Cash Paid for Intangible Assets	65	166	136	296
Cable Communications [Member]
Financial Data by Business Segment
Revenue	14,450	13,912	28,730	27,615
Cable Networks [Member]
Financial Data by Business Segment
Revenue	2,947	2,874	5,815	6,031
Cable Networks [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	2,947	2,874	5,815	6,031
Broadcast Television [Member]
Financial Data by Business Segment
Revenue	2,402	2,391	4,869	5,888
Broadcast Television [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	2,402	2,391	4,869	5,888
Filmed Entertainment [Member]
Financial Data by Business Segment
Revenue	1,457	1,710	3,225	3,357
Filmed Entertainment [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	1,457	1,710	3,225	3,357
Theme Parks [Member]
Financial Data by Business Segment
Revenue	1,464	1,361	2,740	2,642
Theme Parks [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	1,464	1,361	2,740	2,642
NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue	8,206	8,273	16,519	17,770
Adjusted EBITDA	2,324	2,150	4,661	4,421
Depreciation and Amortization	527	553	1,042	1,063
Capital Expenditures	473	461	926	730
Cash Paid for Intangible Assets	65	166	136	296
Sky Limited [Member]
Financial Data by Business Segment
Revenue	4,828	0	9,625	0
Operating Segments [Member] \| Cable Communications [Member]
Financial Data by Business Segment
Revenue	14,450	13,912	28,730	27,615
Adjusted EBITDA	5,854	5,449	11,582	10,666
Depreciation and Amortization	2,036	2,023	4,071	4,084
Capital Expenditures	1,594	1,767	2,957	3,458
Cash Paid for Intangible Assets	303	344	626	631
Operating Segments [Member] \| Cable Networks [Member]
Financial Data by Business Segment
Revenue	2,947	2,874	5,815	6,031
Adjusted EBITDA	1,201	1,176	2,463	2,430
Depreciation and Amortization	183	179	365	368
Capital Expenditures	6	8	12	11
Cash Paid for Intangible Assets	4	5	6	9
Operating Segments [Member] \| Cable Networks [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	2,947	2,874	5,815	6,031
Adjusted EBITDA	1,201	1,176	2,463	2,430
Depreciation and Amortization	183	179	365	368
Capital Expenditures	6	8	12	11
Cash Paid for Intangible Assets	4	5	6	9
Operating Segments [Member] \| Broadcast Television [Member]
Financial Data by Business Segment
Revenue	2,402	2,391	4,869	5,888
Adjusted EBITDA	534	417	921	924
Depreciation and Amortization	40	40	79	74
Capital Expenditures	37	32	50	62
Cash Paid for Intangible Assets	3	3	6	75
Operating Segments [Member] \| Broadcast Television [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	2,402	2,391	4,869	5,888
Adjusted EBITDA	534	417	921	924
Depreciation and Amortization	40	40	79	74
Capital Expenditures	37	32	50	62
Cash Paid for Intangible Assets	3	3	6	75
Operating Segments [Member] \| Filmed Entertainment [Member]
Financial Data by Business Segment
Revenue	1,457	1,710	3,225	3,357
Adjusted EBITDA	183	138	547	341
Depreciation and Amortization	20	63	39	91
Capital Expenditures	4	8	8	15
Cash Paid for Intangible Assets	6	8	11	14
Operating Segments [Member] \| Filmed Entertainment [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	1,457	1,710	3,225	3,357
Adjusted EBITDA	183	138	547	341
Depreciation and Amortization	20	63	39	91
Capital Expenditures	4	8	8	15
Cash Paid for Intangible Assets	6	8	11	14
Operating Segments [Member] \| Theme Parks [Member]
Financial Data by Business Segment
Revenue	1,464	1,361	2,740	2,642
Adjusted EBITDA	590	569	1,088	1,064
Depreciation and Amortization	170	167	332	322
Capital Expenditures	378	360	772	542
Cash Paid for Intangible Assets	17	119	36	135
Operating Segments [Member] \| Theme Parks [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	1,464	1,361	2,740	2,642
Adjusted EBITDA	590	569	1,088	1,064
Depreciation and Amortization	170	167	332	322
Capital Expenditures	378	360	772	542
Cash Paid for Intangible Assets	17	119	36	135
Operating Segments [Member] \| Sky Limited [Member]
Financial Data by Business Segment
Revenue	4,828		9,625
Adjusted EBITDA	772		1,435
Depreciation and Amortization	673		1,414
Capital Expenditures	177		436
Cash Paid for Intangible Assets	152		303
Corporate, Non-Segment [Member]
Financial Data by Business Segment
Revenue	56	96	164	339
Adjusted EBITDA	(213)	(192)	(400)	(377)
Depreciation and Amortization	40	27	69	55
Capital Expenditures	19	22	36	35
Cash Paid for Intangible Assets	11	1	13	3
Corporate, Non-Segment [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	45	57	96	108
Adjusted EBITDA	(195)	(138)	(359)	(312)
Depreciation and Amortization	114	104	227	208
Capital Expenditures	48	53	84	100
Cash Paid for Intangible Assets	35	31	77	63
Corporate, Non-Segment [Member] \| NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue	22	15	39	29
Adjusted EBITDA	(182)	(148)	(356)	(336)
Depreciation and Amortization	114	104	227	208
Capital Expenditures	48	53	84	100
Cash Paid for Intangible Assets	35	31	77	63
Eliminations [Member]
Financial Data by Business Segment
Revenue	(682)	(546)	(1,321)	(1,198)
Adjusted EBITDA	(21)	10	(9)	(49)
Depreciation and Amortization	0	0	0	0
Capital Expenditures	0	0	0	0
Cash Paid for Intangible Assets	0	0	0	0
Eliminations [Member] \| NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue	(88)	(80)	(173)	(183)
Adjusted EBITDA	(2)	(2)	(2)	(2)
Depreciation and Amortization	0	0	0	0
Capital Expenditures	0	0	0	0
Cash Paid for Intangible Assets	0	0	0	0
Eliminations [Member] \| NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue	(86)	(78)	(169)	(177)
Adjusted EBITDA	(2)	(2)	(2)	(2)
Depreciation and Amortization	0	0	0	0
Capital Expenditures	0	0	0	0
Cash Paid for Intangible Assets	$ 0	$ 0	$ 0	$ 0

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The cash outflow to acquire asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

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