Goodwill and Intangible Assets (Schedule of Change in Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance, beginning of period	$ 32,945	$ 27,316
Acquisitions	3,032	5,661
Adjustments	(257)	(1)
Foreign currency translation	(260)	31
Balance, end of period	35,980	32,945
NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	20,364	14,908
Acquisitions	2,949	5,487
Adjustments	(250)
Foreign currency translation	(260)	31
Balance, end of period	23,323	20,364
Operating Segments [Member] \| Cable Communications [Member]
Goodwill [Roll Forward]
Balance, beginning of period	12,389	12,217
Acquisitions	82	173
Adjustments	174	(1)
Foreign currency translation	0	0
Balance, end of period	12,645	12,389
Operating Segments [Member] \| Cable Networks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	12,947	12,948
Acquisitions	232	17
Adjustments	0	0
Foreign currency translation	(4)	18
Balance, end of period	13,183	12,947
Operating Segments [Member] \| Cable Networks [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	12,947	12,948
Acquisitions	232	17
Adjustments	0
Foreign currency translation	(4)	18
Balance, end of period	13,183	12,947
Operating Segments [Member] \| Broadcast Television [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	767
Acquisitions	0	39
Adjustments	0	0
Foreign currency translation	0	0
Balance, end of period	806	806
Operating Segments [Member] \| Broadcast Television [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	767
Acquisitions	0	39
Adjustments	0
Foreign currency translation	0	0
Balance, end of period	806	806
Operating Segments [Member] \| Filmed Entertainment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	267	211
Acquisitions	2,717	58
Adjustments	0	0
Foreign currency translation	(9)	2
Balance, end of period	2,993	267
Operating Segments [Member] \| Filmed Entertainment [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	267	211
Acquisitions	2,717	58
Adjustments	0
Foreign currency translation	(9)	2
Balance, end of period	2,993	267
Operating Segments [Member] \| Theme Parks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,344	982
Acquisitions	0	5,373
Adjustments	(250)	0
Foreign currency translation	(247)	11
Balance, end of period	6,341	6,344
Operating Segments [Member] \| Theme Parks [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,344	982
Acquisitions	0	5,373
Adjustments	(250)
Foreign currency translation	(247)	11
Balance, end of period	6,341	6,344
Corporate, Non-Segment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	192	191
Acquisitions	1	1
Adjustments	(181)	0
Foreign currency translation	0	0
Balance, end of period	$ 12	$ 192

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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