Earnings per Share - Additional Information (Detail) (USD $)	12 Months Ended		20 Months Ended	1 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012 Stock Repurchase Program	Nov. 17, 2011 Accelerated Share Repurchase Program	May 10, 2011 Accelerated Share Repurchase Program	Dec. 31, 2011 Accelerated Share Repurchase Program
Earnings Per Share [Abstract]
Stock repurchase program, authorized amount			$ 1,000,000,000
Stock repurchase program, authorized amount						$ 500,000,000
Treasury stock, shares acquired	0	0		9,300,000	19,900,000	29,200,000