Investments in Unconsolidated Affiliates - Earnings of Unconsolidated Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity in earnings of unconsolidated affiliates, net of tax	$ 2.6	$ 67.1	$ (74.0)
Non-cash gain related to DNB's issuance of common stock, net of tax	9.9	88.2
Equity Method Investment, Realized Gain (Loss) on Disposal		5.0
D&B Investment
Schedule of Equity Method Investments [Line Items]
Equity in earnings of unconsolidated affiliates, net of tax	2.6	67.1	(74.0)
Equity Method Investment, Realized Gain (Loss) on Disposal		5.0
D&B Investment | Prior to change in accounting policy
Schedule of Equity Method Investments [Line Items]
Equity in earnings of unconsolidated affiliates, net of tax	$ (7.3)	$ (26.1)	$ (74.0)