Contingencies - Schedule of Notes Receivable Balances from Insurance Companies (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]
Balance beginning of period	$ 59.6	$ 76.9
Additions	0.7	1.7
Collections	0.0	(19.0)
Balance end of period	$ 60.3	$ 59.6