Stock Repurchase Program - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended	24 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2013 Executives	Dec. 31, 2012 Executives	Dec. 31, 2011 Executives
Equity [Abstract]
Stock repurchase program, authorized amount	$ 950.0
Stock repurchase from inception		846.2
Stock repurchased during period (in shares)		27,945,611
Strike prices and taxes due on exercised stock options and vested restricted stock (in shares)		2,651,238
Acquired shares from repurchase program		30,596,849
Treasury shares cancelled and retired, shares	30,497,699
Treasury shares cancelled and retired, reduction in common stock	51.1
Treasury shares cancelled and retired, reduction in retained earnings	$ 885.1
Equity, Class of Treasury Stock [Line Items]
Stock surrendered during period (in shares)			3,378	9,529	179,221