Share-based Compensation Awards (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stock-based Payment Award
Vesting period in which the fair value of shares on grant date is amortized over, years	2 years
Stock-settled awards
Stock-based Payment Award
Awards granted	1.4	1.4	1.3
Weighted-average grant-date fair value (per award)	$ 31.39	$ 35.54	$ 36.36
Total fair value of vested awards distributed	$ 20.6	$ 60.8	$ 59.7
Accrued dividends on non-vested stock-settled awards	3.7	3.0
Dividends paid for stock-settled awards	$ 2.1	$ 5.3
Cash-settled awards
Stock-based Payment Award
Awards granted	0.1	0.0	0.0
Weighted-average grant-date fair value (per award)	$ 31.40	$ 35.71	$ 36.53
Total fair value of vested awards distributed	$ 0.0	$ 0.8	$ 0.8
Performance-based awards
Stock-based Payment Award
Awards granted	2.8	2.1	1.6
Weighted-average grant-date fair value (per award)	$ 27.53	$ 26.31	$ 29.95
Total fair value of vested awards distributed	$ 9.4	$ 84.8	$ 54.5