Earnings Per Common Share - Additional Information (Detail) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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)	1.9	2.9	5.2
Minimum exercise price range	$ 70.96	$ 70.96	$ 56.28
Maximum exercise price range	$ 88.81	$ 88.81	$ 88.81
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants outstanding	4.1