Condensed Consolidated Statement of Changes in Equity (USD $) In Millions	Total	Redeemable Noncontrolling Interests And Redeemable Subisdiary Preferred Stock [Member]	Class A Common Stock [Member]	ClassA Special Common Stock [Member]	Class B Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock at Cost [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2011	$ 47,655	$ 16,014	$ 25	$ 7	$ 0	$ 40,940	$ 13,971	$ (7,517)	$ (152)	$ 381
Stock compensation plans	142					224	(82)
Repurchase and retirements of common stock	(750)			(1)		(292)	(457)
Employee stock purchase plans	19					19
Dividends declared	(439)						(439)
Other comprehensive income (loss)	4								4
Purchase of subsidiary shares from noncontrolling interests, net	2	(44)				2
Contributions from (distributions to) noncontrolling interests, net	(39)	(8)								(39)
Other	(24)									(24)
Net income (loss)	1,251	196					1,224			27
Ending Balance at Mar. 31, 2012	47,821	16,158	25	6	0	40,893	14,217	(7,517)	(148)	345
Beginning Balance at Dec. 31, 2012	49,796	16,998	25	6	0	40,547	16,280	(7,517)	15	440
Stock compensation plans	21					146	(125)
Repurchase and retirements of common stock	(500)					(152)	(348)
Employee stock purchase plans	22					22
Dividends declared	(514)						(514)
Other comprehensive income (loss)		(9)
Purchase of NBCUniversal noncontrolling common equity interest	(1,508)	(17,006)				(1,482)			(26)
Redeemable subsidiary preferred stock		725
Contributions from (distributions to) noncontrolling interests, net	(31)	(9)								(31)
Other	(121)	(4)				(124)				3
Net income (loss)	1,486	159					1,437			49
Ending Balance at Mar. 31, 2013	$ 48,651	$ 854	$ 25	$ 6	$ 0	$ 38,957	$ 16,730	$ (7,517)	$ (11)	$ 461