Stock-Based Compensation - Analysis of Option Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Options
Options Outstanding-beginning of year	7,889,321	8,579,202	10,998,206
Options Exercised	(1,576,485)	(2,210,348)	(3,917,757)
Options Expired and forfeited	(95,621)	(3,488)	(128,109)
Adjustment to options for stock split		(27)
Options Outstanding-end of year	7,734,841	7,889,321	8,579,202
Options Exercisable at end of year	3,774,061	3,809,415	4,395,552
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price [Abstract]
Outstanding-beginning of year, weighted average exercise price	$ 32.91	$ 27.84	$ 25.43
Options exercised in the period - weighted average exercise price	22.81	25.47	24.97
Options expired and forfeited in the period - weighted average exercise price	48.85	40.05	32.33
Outstanding-end of year, weighted average exercise price	38.84	32.91	27.84
Exercisable at end of year, weighted average exercise price	$ 29.37	$ 24.58	$ 22.95
7-year term [Member]
Options
Options Granted	1,220,751	1,226,270	1,361,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price [Abstract]
Options granted in the period- weighted average exercise price	$ 53.62	$ 50.70	$ 37.62
10-year term [Member]
Options
Options Granted	296,875	297,712	265,162
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price [Abstract]
Options granted in the period- weighted average exercise price	$ 53.61	$ 50.69	$ 37.40