Accounting Changes and Error Corrections (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Premiums receivable	$ 14.1		$ 13.6
Due from Affiliates	18.3		7.9
Assets	3,068.5		2,985.4
Premiums receivables	(0.5)	$ (3.2)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	8.5	(51.8)
Net cash provided by (used in) operating activities	$ 21.8	(43.9)
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Premiums receivable			0.0
Due from Affiliates			21.5
Assets			2,985.4
Premiums receivables		0.0
Increase (Decrease) in Other Operating Assets and Liabilities, Net		55.0
Net cash provided by (used in) operating activities		(43.9)
Revision of Prior Period, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Premiums receivable			13.6
Due from Affiliates			(13.6)
Assets			$ 0.0
Premiums receivables		(3.2)
Increase (Decrease) in Other Operating Assets and Liabilities, Net		(3.2)
Net cash provided by (used in) operating activities		$ 0.0