Share-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Shares
Stock options outstanding - balance at beginning of period (in shares) | shares	15,989
Granted (in shares) | shares	1,503
Forfeited (in shares) | shares	(52)
Exercised (in shares) | shares	(899)
Stock options outstanding - balance at end of period (in shares) | shares	16,541
Stock options exercisable (in shares) | shares	13,646
Weighted-Average Exercise Price
Stock options outstanding - balance at beginning of period (in dollars per shares) | $ / shares	$ 42.83
Granted (in dollars per share) | $ / shares	112.87
Forfeited (in dollars per share) | $ / shares	81.53
Exercised (in dollars per share) | $ / shares	33.09
Stock options outstanding - balance at end of period (in dollars per shares) | $ / shares	49.61
Stock options exercisable (in dollars per share) | $ / shares	$ 40.06
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term, stock options outstanding	5 years 3 months
Weighted average remaining contractual term, stock options exercisable	4 years 5 months 8 days
Aggregate intrinsic value, stock options outstanding | $	$ 778
Aggregate intrinsic value, stock options exercisable | $	$ 750