Stockholders' Equity (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Sep. 26, 2011	Aug. 03, 2011
Cash Dividends [Abstract]
Cash dividends on common stock		$ 0.00	$ 0.00	$ 0.35
Treasury Stock [Abstract]
Stock repurchase program, number of shares authorized					4.0	0.7
Repurchase of common stock, shares		4.7
Treasury stock, value repurchased	$ 95	$ 101	$ 2	$ 2