CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) Share data in Thousands, except Per Share data	Sep. 30, 2011	Dec. 31, 2010
Total cash, cash equivalents, and marketable securities, securities loaned	$ 4,727,000,000	$ 4,031,000,000
Accounts receivable, allowance	145,000,000	101,000,000
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	100,000	100,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A and Class B common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	9,000,000	9,000,000
Common stock, par value	324,000	321,000
Common stock, shares issued	323,757	321,301
Common stock, shares outstanding	323,757	321,301
Class A Common Stock
Common stock, par value	256,000	250,000
Common stock, shares issued	255,703	250,413
Common stock, shares outstanding	255,703	250,413
Class B Common Stock
Common stock, par value	$ 68,000	$ 71,000
Common stock, shares issued	68,054	70,888
Common stock, shares outstanding	68,054	70,888