Contingencies - Summary of Notes Receivable from Insurance Companies and Activity During the Year (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]
Balance beginning of period	$ 59.6	$ 76.9
Additions	1.5	1.7
Collections	(5.1)	(19.0)
Balance end of period	$ 56.0	$ 59.6