Stock Plans and Share-Based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Stock Options Outstanding
Outstanding at December 31, 2019 (in shares) | shares	3,795
Granted (in shares) | shares	1,339
Forfeited (in shares) | shares	(131)
Exercised (in shares) | shares	(786)
Outstanding at December 31, 2020 (in shares) | shares	4,217
Exercisable at December 31, 2020 (in shares) | shares	1,257
Weighted-Average Exercise Price
Outstanding at December 31, 2019 (in dollars per share) | $ / shares	$ 49.78
Granted (in dollars per share) | $ / shares	79.58
Forfeited (in dollars per share) | $ / shares	72.04
Exercised (in dollars per share) | $ / shares	37.41
Outstanding at December 31, 2020 (in dollars per share) | $ / shares	60.88
Exercisable at December 31, 2020 (in dollars per share) | $ / shares	$ 40.05
Outstanding at December 31, 2020, Weighted-average remaining contractual life (in years)	7 years 6 months
Exercisable at December 31, 2020, Weighted-average remaining contractual life (in years)	6 years
Outstanding at December 31, 2020, Aggregate intrinsic value | $	$ 126
Exercisable at December 31, 2020, Aggregate intrinsic value | $	$ 64