Stockholders' Equity - Common Stock Rollforward (Detail) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Shares of common stock issued
Shares at January 1	518.6	516.0	513.0
Exercise of stock options	2	1	1
Issuance of restricted stock	2	2	2
Shares at December 31	522.5	518.6	516.0
Shares of common stock held in treasury
Shares at January 1	18.1	18.0	17.0
Shares received for restricted stock vested and options exercised	1	0	1
Shares at December 31	18.8	18.1	18.0
Shares of common stock outstanding at December 31	504	501	498