Commitments and Contingencies Obligation Reserves (Details) - Total indemnity reserves - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	$ 14.2	$ 14.7	$ 17.3
Changes in estimates	0.0	0.0	0.0
Foreign exchange impacts	(3.2)	(0.5)	(2.6)
Balance at end of period	$ 11.0	$ 14.2	$ 14.7