Life, Accident and Health Reserves - Liability for Claims of Long-Term Care Insurance Reserves (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance	$ 4,567.1
Paid related to insured events of:
Ending balance	4,593.9
Other Long Duration Insurance Product Line
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance	761.3	$ 738.7
Less: recoverable from reinsurers	(131.0)	(136.4)
Beginning balance, net	630.3	602.3
Incurred related to insured events of:
Current year	68.9	62.4
Prior years	(13.3)	(36.0)
Total incurred	55.6	26.4
Paid related to insured events of:
Current year	(0.6)	(0.6)
Prior years	(42.8)	(36.4)
Total paid	(43.4)	(37.0)
Interest on liability for policy and contract claims	5.6	5.3
Ending balance, net	648.1	597.0
Add: recoverable from reinsurers	136.2	136.4
Ending balance	$ 784.3	$ 733.4