Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Nov. 30, 2006
Stockholders Equity Note [Line Items]
Sold warrants to acquire shares of our common stock						215,000,000
Sold warrants to acquire shares of our common stock, exercise price per share						$ 19.55
Common stock excluded from calculation of diluted earnings per share		13,300,000	54,500,000	162,000,000
Repurchases of Common Stock, shares authorized to repurchase					250,000,000
Total Repurchases of Common Stock, shares		195,800,000
Total Repurchases of Common Stock		$ 3,700,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased		54,200,000
Repurchases of Common Stock		1,999,968,000	999,924,000
Repurchases of Common Stock, shares		81,810,000
Shares authorized for future repurchases	$ 700,000,000