Discontinued Operations - Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Accounts payable and accrued expenses	$ 62.3	$ 58.8
Other noncurrent liabilities	91.4	105.5
Total liabilities classified as discontinued operations	$ 153.7	$ 164.3