Share-Based Payments - Stock Option Activities (Details) - Stock Option Plan $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
Stock option activity, shares
Stock options at the beginning of the period (in shares) | shares	11,297
Stock options, granted (in shares) | shares	754
Stock options, exercised (in shares) | shares	(1,677)
Stock options, forfeited (in shares) | shares	(700)
Stock options, expired (in shares) | shares	(18)
Stock options at the end of the period (in shares) | shares	9,656
Stock options, vested and expected to vest (in shares) | shares	9,260
Stock options, exercisable (in shares) | shares	5,015
Weighted-average exercise price per stock option
Stock options, weighted-average strike price at the beginning of the period (in dollars per share) | $ / shares	$ 53.84
Stock options, weighted-average exercise price, granted (in dollars per share) | $ / shares	92.56
Stock options, weighted-average exercise price, exercised (in dollars per share) | $ / shares	46.27
Stock options, weighted-average exercise price, forfeited (in dollars per share) | $ / shares	63.58
Stock options, weighted-average exercise price, expired (in dollars per share) | $ / shares	56.58
Stock options, weighted-average strike price at the end of the period (in dollars per share) | $ / shares	57.47
Stock options, weighted-average exercise price, vested and expected to vest (in dollars per share) | $ / shares	56.62
Stock options, weighted-average exercise price, exercisable (in dollars per share) | $ / shares	$ 45.46
Stock options, weighted-average remaining contractual term	7 years 2 months 4 days
Stock options, weighted-average remaining contractual term, vested and expected to vest	7 years 1 month 6 days
Stock options, weighted-average remaining contractual term, exercisable	6 years
Stock options, aggregate intrinsic value | $	$ 211
Stock options, aggregate intrinsic value, vested and expected to vest | $	208
Stock options, aggregate intrinsic value, exercisable | $	160
Share-based compensation, unrecognized compensation | $	$ 44
Share-based compensation, unrecognized compensation weighted-average period of recognition	1 year 1 month 6 days