Shareholders' Equity (Details Textuals) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2011
Shareholders' Equity (Textuals) [Abstract]
Aggregate value of common stock repurchased under accelerated share repurchase agreement	$ 300		$ 300
Number of shares received and cancelled			7
Weighted average price of share repurchase			$ 42.64
The maximum number of shares of our Class A common stock that may be repurchased every year			Equal to the total number of shares issued pursuant to our equity awards in the previous year and the current year
Repurchased shares of our Class A common stock	0	0	10	9
Weighted average price for repurchase of stock			$ 36.84	$ 30.65
Percentage increase in cash dividend			12.50%
Dividends per share	$ 0.09	$ 0.08	$ 0.27	$ 0.24	$ 0.36
Dividends paid	$ 48	$ 41	$ 145	$ 121