Net Income Per Share - Reconciliation between Basic and Diluted Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income	$ 235.5	$ 220.3
Net income attributable to unvested awarded performance stock	(4.0)	(4.4)
Net income attributable to common shares	$ 231.5	$ 215.9
Weighted average number of common shares outstanding – basic	283.4	282.8
Less unvested awarded performance stock included in weighted average number of common shares outstanding - basic	(4.8)	(5.7)
Weighted average number of common shares outstanding for basic net income per common share	278.6	277.1
Dilutive effect of potentially issuable common shares	0.8	1.5
Weighted average number of shares outstanding – diluted	279.4	278.6
Basic (in dollars per share)	$ 0.83	$ 0.78
Diluted (in dollars per share)	$ 0.83	$ 0.77