Share-based Compensation - Summary of Stock-based Compensation Activity (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options - Exercised	(200)	(3,300)	(2,300)
Options - Outstanding at end of period	6,910
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value on date of grant - Outstanding at beginning of period	$ 71.58
Weighted average fair value on date of grant - Granted	74.38
Weighted average fair value on date of grant - Vested	63.63
Weighted average fair value on date of grant - Forfeited	71.39
Weighted average fair value on date of grant - Outstanding at end of period	$ 75.32	$ 71.58
Awards - Outstanding at beginning of period	2,901
Awards - Granted	1,131
Awards - Vested	(921)
Awards - Forfeited	(291)
Awards - Outstanding at end of period	2,820	2,901
Vesting period from date of grant, in years	3 years
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average exercise price per share - Outstanding at beginning of period	$ 66.79
Weighted average exercise price per share - Granted	74.49
Weighted average exercise price per share - Exercised	48.51
Weighted average exercise price per share - Forfeited	79.29
Weighted average exercise price per share - Outstanding at end of period	$ 67.77	$ 66.79
Options - Outstanding at beginning of period	6,766
Options - Granted	521
Options - Exercised	(244)
Options - Forfeited	(132)
Options - Outstanding at end of period	6,911	6,766
Vesting period from date of grant, in years	3 years
Performance Share Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value on date of grant - Outstanding at beginning of period	$ 89.91
Weighted average fair value on date of grant - Granted	76.64
Weighted average fair value on date of grant - Vested	72.93
Weighted average fair value on date of grant - Forfeited	97.16
Weighted average fair value on date of grant - Outstanding at end of period	$ 89.43	$ 89.91
Awards - Outstanding at beginning of period	800
Awards - Granted	366
Awards - Vested	(288)
Awards - Forfeited	(58)
Awards - Outstanding at end of period	820	800
Vesting period from date of grant, in years	3 years