Goodwill and Intangible Assets (Schedule of Change in Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance, beginning of period	$ 36,780	$ 35,980
Goodwill, Acquired During Period	29,925	418
Dispositions	(13)	(11)
Adjustments	(21)	186
Foreign currency translation	(517)	207
Balance, end of period	66,154	36,780
NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	23,989	23,323
Goodwill, Acquired During Period	36	273
Dispositions	(8)
Adjustments	(21)	186
Foreign currency translation	122	207
Balance, end of period	24,118	23,989
Operating Segments [Member] \| Cable Communications [Member]
Goodwill [Roll Forward]
Balance, beginning of period	12,784	12,645
Goodwill, Acquired During Period	0	140
Dispositions	0	0
Adjustments	0	(1)
Foreign currency translation	0	0
Balance, end of period	12,784	12,784
Operating Segments [Member] \| Cable Networks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	13,427	13,183
Goodwill, Acquired During Period	0	241
Dispositions	0	0
Adjustments	(13)	1
Foreign currency translation	(7)	2
Balance, end of period	13,407	13,427
Operating Segments [Member] \| Cable Networks [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	13,427	13,183
Goodwill, Acquired During Period	0	241
Dispositions	0
Adjustments	(13)	1
Foreign currency translation	(7)	2
Balance, end of period	13,407	13,427
Operating Segments [Member] \| Broadcast Television [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	806
Goodwill, Acquired During Period	36	0
Dispositions	0	0
Adjustments	1	0
Foreign currency translation	0	0
Balance, end of period	843	806
Operating Segments [Member] \| Broadcast Television [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	806
Goodwill, Acquired During Period	36	0
Dispositions	0
Adjustments	1	0
Foreign currency translation	0	0
Balance, end of period	843	806
Operating Segments [Member] \| Filmed Entertainment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	3,212	2,993
Goodwill, Acquired During Period	0	32
Dispositions	(8)	0
Adjustments	(9)	185
Foreign currency translation	(11)	2
Balance, end of period	3,184	3,212
Operating Segments [Member] \| Filmed Entertainment [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	3,212	2,993
Goodwill, Acquired During Period	0	32
Dispositions	(8)
Adjustments	(9)	185
Foreign currency translation	(11)	2
Balance, end of period	3,184	3,212
Operating Segments [Member] \| Theme Parks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,544	6,341
Goodwill, Acquired During Period	0	0
Dispositions	0	0
Adjustments	0	0
Foreign currency translation	140	203
Balance, end of period	6,684	6,544
Operating Segments [Member] \| Theme Parks [Member] \| NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,544	6,341
Goodwill, Acquired During Period	0	0
Dispositions	0
Adjustments	0	0
Foreign currency translation	140	203
Balance, end of period	6,684	6,544
Operating Segments [Member] \| Sky Limited [Member]
Goodwill [Roll Forward]
Balance, beginning of period	0	0
Goodwill, Acquired During Period	29,889	0
Dispositions	0	0
Adjustments	0	0
Foreign currency translation	(639)	0
Balance, end of period	29,250	0
Corporate, Non-Segment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	7	12
Goodwill, Acquired During Period	0	5
Dispositions	(5)	(11)
Adjustments	0	1
Foreign currency translation	0	0
Balance, end of period	$ 2	$ 7

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.

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