Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Balance Sheet Parentheticals [Abstract]
Receivables, allowances	$ 103	$ 114
Class A Common Stock
Class Of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	375,000,000	375,000,000
Common stock, shares, issued	43,000,000	44,000,000
Class B Common Stock
Class Of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	5,000,000,000	5,000,000,000
Common stock, shares, issued	783,000,000	769,000,000
Treasury stock, at cost, Class B shares	189,000,000	162,000,000