Share-Based Compensation - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding stock options, Beginning balance | shares	7,763
Options granted | shares	1,488
Options exercised | shares	(1,633)
Options forfeited | shares	(303)
Options expired | shares	(30)
Outstanding stock options, Ending Balance | shares	7,285
Number of outstanding options, Vested or expected to vest | shares	7,057
Exercisable, Stock options | shares	3,890
Outstanding Weighted average exercise price, Beginning Balance | $ / shares	$ 100.29
Options granted, Weighted average exercise price | $ / shares	123.76
Options exercised, Weighted average exercise price | $ / shares	85.97
Options forfeited, Weighted average exercise price | $ / shares	117.28
Options expired, Weighted average exercise price | $ / shares	115.12
Outstanding Weighted average exercise price, ending Balance | $ / shares	107.53
Outstanding Weighted average exercise price, Vested or expected to vest | $ / shares	107.10
Exercisable, Weighted average exercise price | $ / shares	$ 97.15
Weighted Average Remaining Contractual Life, Outstanding at December 31, 2019	6 years 7 months 6 days
Weighted Average Remaining Contractual Life, Vested or expected to vest as of December 31, 2019	6 years 7 months 6 days
Weighted Average Remaining Contractual Life, Exercisable at December 31, 2019	5 years 1 month 6 days
Intrinsic Value, Outstanding at December 31, 2019 | $	$ 307.1
Intrinsic Value, Vested or expected to vest as of December 31, 2019 | $	300.5
Intrinsic Value, Exercisable at December 31, 2019 | $	$ 204.3