Financial Data by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue	$ 18,669	$ 16,791	$ 55,265	$ 51,043
Operating income (loss) before depreciation and amortization	6,184	5,704	18,406	17,046
Depreciation and amortization	2,183	1,959	6,410	5,929
Operating income (loss)	4,001	3,745	11,996	11,117
Capital expenditures	$ 2,165	$ 1,950	$ 5,862	$ 5,196
Cable segment revenue types as percentage of total cable revenue	100.00%	100.00%	100.00%	100.00%
NBCUniversal Media, LLC [Member]
Revenue	$ 7,151	$ 5,921	$ 20,985	$ 18,813
Operating income (loss) before depreciation and amortization	1,601	1,416	4,807	4,161
Depreciation and amortization	380	371	1,149	1,106
Operating income (loss)	1,221	1,045	3,658	3,055
Capital expenditures	289	295	829	884
Cable Communications [Member]
Revenue	11,740	11,041	34,899	32,827
Operating income (loss) before depreciation and amortization	4,748	4,464	14,220	13,428
Depreciation and amortization	1,777	1,561	5,178	4,749
Operating income (loss)	2,971	2,903	9,042	8,679
Capital expenditures	1,851	1,644	4,972	4,282
Cable Networks [Member]
Revenue	2,412	2,255	7,221	7,236
Operating income (loss) before depreciation and amortization	835	868	2,605	2,677
Depreciation and amortization	193	189	588	558
Operating income (loss)	642	679	2,017	2,119
Capital expenditures	9	11	20	30
Cable Networks [Member] \| NBCUniversal Media, LLC [Member]
Revenue	2,412	2,255	7,221	7,236
Operating income (loss) before depreciation and amortization	835	868	2,605	2,677
Depreciation and amortization	193	189	588	558
Operating income (loss)	642	679	2,017	2,119
Capital expenditures	9	11	20	30
Broadcast Television [Member]
Revenue	1,971	1,770	6,032	6,207
Operating income (loss) before depreciation and amortization	150	142	563	504
Depreciation and amortization	26	24	85	78
Operating income (loss)	124	118	478	426
Capital expenditures	28	15	53	52
Broadcast Television [Member] \| NBCUniversal Media, LLC [Member]
Revenue	1,971	1,770	6,032	6,207
Operating income (loss) before depreciation and amortization	150	142	563	504
Depreciation and amortization	26	24	85	78
Operating income (loss)	124	118	478	426
Capital expenditures	28	15	53	52
Filmed Entertainment [Member]
Revenue	1,946	1,186	5,658	3,713
Operating income (loss) before depreciation and amortization	376	151	1,091	634
Depreciation and amortization	8	6	19	16
Operating income (loss)	368	145	1,072	618
Capital expenditures	2	4	7	8
Filmed Entertainment [Member] \| NBCUniversal Media, LLC [Member]
Revenue	1,946	1,186	5,658	3,713
Operating income (loss) before depreciation and amortization	376	151	1,091	634
Depreciation and amortization	8	6	19	16
Operating income (loss)	368	145	1,072	618
Capital expenditures	2	4	7	8
Theme Parks [Member]
Revenue	896	786	2,320	1,888
Operating income (loss) before depreciation and amortization	458	402	1,075	816
Depreciation and amortization	72	68	214	210
Operating income (loss)	386	334	861	606
Capital expenditures	156	184	484	486
Theme Parks [Member] \| NBCUniversal Media, LLC [Member]
Revenue	896	786	2,320	1,888
Operating income (loss) before depreciation and amortization	458	402	1,075	816
Depreciation and amortization	72	68	214	210
Operating income (loss)	386	334	861	606
Capital expenditures	156	184	484	486
Headquarters And Other [Member]
Revenue	5	4	12	10
Operating income (loss) before depreciation and amortization	(164)	(142)	(473)	(464)
Depreciation and amortization	81	84	243	244
Operating income (loss)	(245)	(226)	(716)	(708)
Capital expenditures	94	81	265	308
Headquarters And Other [Member] \| NBCUniversal Media, LLC [Member]
Revenue	5	4	12	10
Operating income (loss) before depreciation and amortization	(164)	(142)	(473)	(464)
Depreciation and amortization	81	84	243	244
Operating income (loss)	(245)	(226)	(716)	(708)
Capital expenditures	94	81	265	308
NBCUniversal Eliminations [Member]
Revenue	(79)	(80)	(258)	(241)
Operating income (loss) before depreciation and amortization	2	(5)	2	(6)
Depreciation and amortization	0	0	0	0
Operating income (loss)	2	(5)	2	(6)
Capital expenditures	0	0	0	0
NBCUniversal Eliminations [Member] \| NBCUniversal Media, LLC [Member]
Revenue	(79)	(80)	(258)	(241)
Operating income (loss) before depreciation and amortization	(54)	(5)	(54)	(6)
Depreciation and amortization	0	0	0	0
Operating income (loss)	(54)	(5)	(54)	(6)
Capital expenditures	0	0	0	0
NBCUniversal [Member]
Revenue	7,151	5,921	20,985	18,813
Operating income (loss) before depreciation and amortization	1,657	1,416	4,863	4,161
Depreciation and amortization	380	371	1,149	1,106
Operating income (loss)	1,277	1,045	3,714	3,055
Capital expenditures	289	295	829	884
Corporate and Other [Member]
Revenue	180	174	560	520
Operating income (loss) before depreciation and amortization	(232)	(197)	(709)	(532)
Depreciation and amortization	26	27	83	74
Operating income (loss)	(258)	(224)	(792)	(606)
Capital expenditures	25	11	61	30
Eliminations [Member]
Revenue	(402)	(345)	(1,179)	(1,117)
Operating income (loss) before depreciation and amortization	11	21	32	(11)
Depreciation and amortization	0	0	0	0
Operating income (loss)	11	21	32	(11)
Capital expenditures	$ 0	$ 0	$ 0	$ 0
Cable Communications Segment Revenue Percentage-Video [Member]
Cable segment revenue types as percentage of total cable revenue	45.60%	46.90%	46.20%	47.50%
Cable Communications Segment Revenue Percentage - High-speed Internet [Member]
Cable segment revenue types as percentage of total cable revenue	26.70%	25.70%	26.60%	25.60%
Cable Communications Segment Revenue Percentage- Voice [Member]
Cable segment revenue types as percentage of total cable revenue	7.70%	8.30%	7.80%	8.40%
Cable Communications Segment Revenue Percentage- Business Services [Member]
Cable segment revenue types as percentage of total cable revenue	10.30%	9.20%	10.00%	8.80%
Cable Communications Segment Revenue Percentage- Advertising [Member]
Cable segment revenue types as percentage of total cable revenue	5.10%	5.40%	4.80%	5.10%
Cable Communications Segment Revenue Percentage- Other [Member]
Cable segment revenue types as percentage of total cable revenue	4.60%	4.50%	4.60%	4.60%
Cable Communications Segment Revenue Percentage- Franchise and other regulatory fees [Member]
Cable segment revenue types as percentage of total cable revenue	2.80%	2.80%	2.80%	2.80%

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