Schedule 4 - Reinsurance Schedule (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct Premiums, Life Insurance in Force	$ 20,209.8				$ 20,565.9				$ 20,209.8	$ 20,565.9	$ 21,006.0
Direct Premiums Earned									1,970.1	1,831.1	2,007.0
Ceded Premiums, Life Insurance in Force	514.2				541.5				514.2	541.5	576.4
Ceded to Other Companies									20.6	26.0	33.9
Assumed Premiums, Life Insurance in Force	205.7				217.8				205.7	217.8	229.5
Assumed Premiums Earned									60.1	57.1	52.7
Premiums, Net, Life Insurance in Force	19,901.3				20,242.2				19,901.3	20,242.2	20,659.1
Net Amount	$ 541.5	$ 536.7	$ 500.1	$ 431.3	$ 451.5	$ 462.8	$ 470.3	$ 477.6	$ 2,009.6	$ 1,862.2	$ 2,025.8
Life Insurance in Force Premiums, Percentage Assumed to Net	1.00%				1.10%				1.00%	1.10%	1.10%
Premiums, Percentage Assumed to Net									3.00%	3.10%	2.60%
Life Insurance Product Line [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct Premiums Earned									$ 374.1	$ 387.5	$ 392.4
Ceded to Other Companies									1.4	1.5	1.5
Assumed Premiums Earned									1.4	1.6	1.8
Net Amount									$ 374.1	$ 387.6	$ 392.7
Premiums, Percentage Assumed to Net									0.40%	0.40%	0.50%
Accident and Health Insurance [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct Premiums Earned									$ 139.8	$ 146.3	$ 161.9
Ceded to Other Companies									0.5	0.5	0.6
Assumed Premiums Earned									5.6	2.8	0.1
Net Amount									$ 144.9	$ 148.6	$ 161.4
Premiums, Percentage Assumed to Net									3.90%	1.90%	0.10%
Property, Liability and Casualty Insurance [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct Premiums Earned									$ 1,456.2	$ 1,297.3	$ 1,452.7
Ceded to Other Companies									18.7	24.0	31.8
Assumed Premiums Earned									53.1	52.7	50.8
Net Amount									$ 1,490.6	$ 1,326.0	$ 1,471.7
Premiums, Percentage Assumed to Net									3.60%	4.00%	3.50%