Stockholders' Equity - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	2 Months Ended	3 Months Ended		6 Months Ended		18 Months Ended	36 Months Ended	60 Months Ended	63 Months Ended				1 Months Ended
	Feb. 27, 2013	Jul. 23, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2014	Dec. 31, 2015	Mar. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Dec. 31, 2008	Nov. 30, 2006	Nov. 30, 2006 Sold Warrants
Accumulated Other Comprehensive Income (Loss), Net of Tax			$ (299,000,000)		$ (299,000,000)					$ (299,000,000)	$ (208,000,000)
Sold warrants to acquire shares of our common stock														215
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			4	3		4
Repurchases of Common Stock, shares authorized to repurchase			500		500					500		250
Total Repurchases of Common Stock, shares									42	264
Total Repurchases of Common Stock									1,000,000,000	5,400,000,000
Shares authorized for future repurchases			236		236					236
Stock Repurchase Program, Additional Number of Shares Authorized to be Repurchased	250
Plan to spend for the year on common stock repurchases							3,500,000,000	6,000,000,000
Cash dividends declared per common share			$ 0.10	$ 0.00	$ 0.10	$ 0.00
Common Stock, Dividends, Per Share, Cash Paid		$ 208,000,000