Financial Data by Business Segment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenue	$ 16,270	$ 15,211	$ 31,580	$ 30,089
Operating income (loss) before depreciation and amortization	5,425	5,004	10,459	9,692
Depreciation and amortization	1,990	1,925	3,957	3,855
Operating income (loss)	3,435	3,079	6,502	5,837
Capital expenditures	1,506	1,287	2,867	2,461
Cable segment revenue types as percentage of total cable revenue	100.00%	100.00%	100.00%	100.00%
Cable Communications [Member]
Revenue	10,467	9,897	20,684	19,496
Operating income (loss) before depreciation and amortization	4,335	4,101	8,554	8,056
Depreciation and amortization	1,623	1,593	3,231	3,195
Operating income (loss)	2,712	2,508	5,323	4,861
Capital expenditures	1,240	1,124	2,334	2,180
Cable Networks [Member]
Revenue	2,413	2,240	4,638	4,368
Operating income (loss) before depreciation and amortization	860	790	1,719	1,599
Depreciation and amortization	182	182	366	358
Operating income (loss)	678	608	1,353	1,241
Capital expenditures	24	22	48	31
Broadcast Television [Member]
Revenue	1,732	1,552	3,249	3,413
Operating income (loss) before depreciation and amortization	206	194	171	180
Depreciation and amortization	26	22	51	45
Operating income (loss)	180	172	120	135
Capital expenditures	9	11	17	19
Filmed Entertainment [Member]
Revenue	1,388	1,231	2,604	2,423
Operating income (loss) before depreciation and amortization	33	(83)	102	(77)
Depreciation and amortization	3	4	7	8
Operating income (loss)	30	(87)	95	(85)
Capital expenditures	1	3	3	4
Theme Parks [Member]
Revenue	546	539	1,008	951
Operating income (loss) before depreciation and amortization	231	235	404	392
Depreciation and amortization	73	63	145	125
Operating income (loss)	158	172	259	267
Capital expenditures	147	52	285	99
Headquarters And Other [Member]
Revenue	9	11	18	23
Operating income (loss) before depreciation and amortization	(137)	(155)	(249)	(301)
Depreciation and amortization	65	48	124	96
Operating income (loss)	(202)	(203)	(373)	(397)
Capital expenditures	79	68	170	114
NBCUniversal Eliminations [Member]
Revenue	(93)	(69)	(182)	(202)
Operating income (loss) before depreciation and amortization	(2)	1	(3)	2
Depreciation and amortization	0	1	0	0
Operating income (loss)	(2)	0	(3)	2
Capital expenditures	0	0	0	0
NBCUniversal [Member]
Revenue	5,995	5,504	11,335	10,976
Operating income (loss) before depreciation and amortization	1,191	982	2,144	1,795
Depreciation and amortization	349	320	693	632
Operating income (loss)	842	662	1,451	1,163
Capital expenditures	260	156	523	267
Corporate and Other [Member]
Revenue	136	130	298	304
Operating income (loss) before depreciation and amortization	(119)	(90)	(202)	(154)
Depreciation and amortization	17	16	32	30
Operating income (loss)	(136)	(106)	(234)	(184)
Capital expenditures	6	7	10	14
Eliminations [Member]
Revenue	(328)	(320)	(737)	(687)
Operating income (loss) before depreciation and amortization	18	11	(37)	(5)
Depreciation and amortization	1	(4)	1	(2)
Operating income (loss)	17	15	(38)	(3)
Capital expenditures	$ 0	$ 0	$ 0	$ 0
Cable Communications Segment Revenue Percentage-Video [Member]
Cable segment revenue types as percentage of total cable revenue	49.40%	50.90%	49.70%	51.10%
Cable Communications Segment Revenue Percentage - High-speed Internet [Member]
Cable segment revenue types as percentage of total cable revenue	24.50%	24.00%	24.60%	24.10%
Cable Communications Segment Revenue Percentage- Phone [Member]
Cable segment revenue types as percentage of total cable revenue	8.70%	9.00%	8.80%	9.10%
Cable Communications Segment Revenue Percentage- Advertising [Member]
Cable segment revenue types as percentage of total cable revenue	5.30%	5.60%	5.10%	5.30%
Cable Communications Segment Revenue Percentage- Business Services [Member]
Cable segment revenue types as percentage of total cable revenue	7.50%	6.30%	7.40%	6.20%
Cable Communications Segment Revenue Percentage- Other [Member]
Cable segment revenue types as percentage of total cable revenue	4.60%	4.20%	4.40%	4.20%
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%	2.90%	2.80%