Contingencies - Schedule of Notes Receivable Balances from Insurance Companies (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]
Balance beginning of period	$ 52.3	$ 56.0
Additions	1.0	1.4
Collections	(5.1)	(5.1)
Balance end of period	$ 48.2	$ 52.3