Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Common Share (Parenthetical) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options excluded from the computation of diluted earnings per share (in shares)	2,300,000.0	4,800,000.0	3,200,000.0	5,500,000.0
Minimum exercise price range	$ 70.96	$ 67.37	$ 70.96	$ 56.28
Maximum exercise price range	$ 88.81	$ 88.81	$ 88.81	$ 88.81
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants outstanding	6,400,000		6,400,000