Stockholders' Equity - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended		12 Months Ended	13 Months Ended				12 Months Ended		1 Months Ended		0 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	May 30, 2013	Feb. 28, 2013	Nov. 30, 2006	Dec. 31, 2015 Scenario, Forecast	Dec. 31, 2014 Scenario, Forecast	Nov. 30, 2006 Sold Warrants	Dec. 31, 2013 Warrant	Apr. 23, 2014 Subsequent Event	Apr. 17, 2014 Subsequent Event
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	6	3
Warrants and Rights Outstanding											$ 109,000,000
Repurchases of Common Stock, shares authorized to repurchase						250
Total Repurchases of Common Stock, shares	16			110
Total Repurchases of Common Stock	405,000,000			2,800,000,000
Shares authorized for future repurchases	140			140
Plan to spend for the year on common stock repurchases	6,000,000,000							1,000,000,000	2,000,000,000
Common Stock Dividend Rate					0.100								0.115
Payments for Repurchase of Common Stock	390,000,000	323,000,000	3,000,000,000
Common Stock, Dividends, Per Share, Cash Paid	$ 202,000,000	$ 0										$ 205,000,000