Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			1 Months Ended			3 Months Ended			12 Months Ended
	Dec. 31, 2020	May 09, 2018	Mar. 31, 2021	Dec. 31, 2020	Oct. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Equity [Abstract]
Common stock issued (in shares)			16.9	13.0	9.6
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01	$ 0.01	$ 0.01				$ 0.01		$ 0.01
Common stock, price per share (in dollars per share)	$ 76.65		$ 91.00	$ 76.65	$ 60.00				76.65
Proceeds from sale of stock	$ 868.6		$ 1,500.0	$ 994.6	$ 557.4
Common stock dividends declared (in dollars per share)							$ 0.78	$ 0.78	$ 0.78	$ 2.96
Common stock, dividends paid (in dollars per share)						$ 0.78	$ 0.78
Term of stock repurchase program		24 months