Net Income Per Share - Schedule of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income - basic and diluted	$ 1,115.2	$ 624.6
Weighted average shares outstanding - basic (in shares)	105.4	109.8
Weighted average shares - diluted (in shares)	110.5	115.1
Net income per share - basic (in dollars per share)	$ 10.58	$ 5.69
Net income per share - diluted (in dollars per share)	$ 10.09	$ 5.43
Stock options
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities (in shares)	4.5	5.0
Restricted stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities (in shares)	0.6	0.3