Stock-Based Compensation - Summary of Option Activity (Details) - Non-qualified stock options - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Options
Outstanding at the beginning of the period	1.3	1.5	1.7
Options granted	0.5	0.2	0.2
Options exercised	(0.2)	(0.4)	(0.4)
Outstanding at the end of the period	1.6	1.3	1.5	1.7
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 47.92	$ 38.97	$ 31.18
Options granted (in dollars per share)	54.82	65.56	68.15
Options exercised (in dollars per share)	32.18	25.95	16.06
Outstanding at the end of the period (in dollars per share)	$ 51.07	$ 47.92	$ 38.97	$ 31.18
Remaining Contractual Life
Remaining Contractual Life	6 years 14 days	5 years 7 months 6 days	5 years 2 months 12 days	5 years 2 months 8 days