Capital Stock - Additional Information (Detail) (USD $) In Billions, except Share data, unless otherwise specified	0 Months Ended			3 Months Ended												12 Months Ended
	Feb. 14, 2014	Feb. 12, 2013	Jul. 30, 2007	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Capital Stock [Line Items]
All classes of stock, shares authorized				1,020,000,000												1,020,000,000
Preferred stock, shares authorized				10,000,000				10,000,000								10,000,000	10,000,000
Amount authorized to be repurchased	$ 1	$ 1	$ 2
Shares repurchased during the period																14,200,000
Shares issued during the period for stock-based compensation plans																5,500,000
Dividends declared per share				$ 0.53	$ 0.25	$ 0.20	$ 0	$ 0.36	$ 0.16	$ 0.16	$ 0	$ 0.30	$ 0.14	$ 0.14	$ 0	$ 0.98	$ 0.68	$ 0.58
Dividends declaration date																Dec. 19, 2013
Dividends payable date																Mar. 11, 2014
Dividends payable record date																Feb. 20, 2014
Common Stock
Schedule Of Capital Stock [Line Items]
Common stock, shares authorized				1,000,000,000				1,000,000,000								1,000,000,000	1,000,000,000
Series common stock
Schedule Of Capital Stock [Line Items]
Common stock, shares authorized				10,000,000				10,000,000								10,000,000	10,000,000