Consolidated Statement of Changes in Equity (USD $) In Millions	Total	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Loss, Net of Tax [Member]	Additional Paid-In Capital [Member]	Class A Treasury Stock [Member]	Non-Controlling Interests [Member]
Balance at Dec. 31, 2011	$ 5,877	$ 4,745	$ (2)	$ 3,519	$ (2,394)	$ 9
Net income (loss)	1,381	1,382				(1)
Contribution by non-controlling interest	3					3
Other comprehensive income, net of tax	(45)		(45)
Cash dividends declared on Class A and Class B common stock, $0.60 per share	(75)	(75)
Purchases of treasury stock	(919)				(919)
Issuance of treasury stock for share-based compensation	0			(2)	2
Share-based payments	41			41
Stock units withheld for taxes	(38)			(38)
Tax benefit for share-based compensation	33			33
Exercise of stock options	18			18
Balance at Jun. 30, 2012	$ 6,276	$ 6,052	$ (47)	$ 3,571	$ (3,311)	$ 11