Stock-Based Compensation Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 20.1	$ 21.9	$ 62.3	$ 75.9
Continuing operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	20.1	21.9	62.3	65.0
Discontinued operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 0.0	$ 0.0	$ 0.0	$ 10.9