Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Income from continuing operations	$ 99.6	$ 194.3
Less: dividends declared	39.0	28.7
Undistributed earnings	$ 60.6	$ 165.6
Percent allocated to common stockholders	99.80%	99.70%
Undistributed earnings allocated to common stockholders	$ 60.5	$ 165.1
Add: dividends declared to common shares, restricted share units and vested and deferred restricted and performance shares	38.9	28.7
Income from continuing operations attributable to common stockholders	$ 99.4	$ 193.8
Shares:
Basic weighted-average shares outstanding (in shares)	51.1	52.1
Effect of dilutive securities:
Performance awards (in shares)	0.2	0.2
Stock options (in shares)	0.4	0.6
Diluted weighted-average shares outstanding (in shares)	51.7	52.9
Per share income from continuing operations attributable to common shares:
Basic (in dollars per share)	$ 1.95	$ 3.72
Diluted (in dollars per share)	$ 1.92	$ 3.67
Basic weighted-average shares outstanding (in shares)	51.1	52.1
Basic weighted-average shares outstanding and unvested restricted shares expected to vest (in shares)	51.2	52.3
Percent allocated to common stockholders	99.80%	99.70%
Anti-dilutive stock options excluded from EPS calculation
Income (loss) from discontinued operations attributable to common stockholders for basic and diluted earnings per share	$ 2.1	$ (0.7)
Net income attributable to common stockholders for basic and diluted earnings per share	$ 101.5	$ 193.1
Anti-dilutive stock options excluded from earnings per share calculation (in shares)	0.7	0.1