Insurance Expenses (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Insurance Expenses [Abstract]
Commissions									$ 708.8	$ 558.7	$ 425.6
General Expenses									278.0	231.9	196.2
Taxes, Licenses and Fees									93.5	71.0	50.7
Total Costs Incurred									1,080.3	861.6	672.5
Policy Acquisition Costs:
Deferred									(475.2)	(481.5)	(351.6)
Amortized									408.3	377.1	318.3
Net Policy Acquisition Costs Amortized									(66.9)	(104.4)	(33.3)
Amortization of VOBA									6.3	143.3	5.1
Insurance Expenses	$ 265.4	$ 256.0	$ 263.5	$ 234.8	$ 273.2	$ 296.0	$ 171.2	$ 160.1	$ 1,019.7	$ 900.5	$ 644.3