BUSINESS SEGMENTS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Fee revenue and other income	$ 12.2	$ 10.5	$ 35.5	$ 38.7
Total revenues	1,036.4	991.3	3,114.6	2,907.6
Expenses:
Insurance policy benefits	638.1	609.8	1,941.6	1,861.2
Other operating costs and expenses	217.5	187.3	631.3	603.5
Total expenses	920.6	893.0	2,784.8	2,632.3
Pre-tax operating earnings	115.8	98.3	329.8	275.3
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	1,036.4	991.3	3,114.6	2,907.6
Net realized investment gains	29.2	11.6	52.3	23.3
Revenues related to VIEs	13.7	13.0	40.2	39.3
Fee revenue related to transition and support services agreements	0.0	0.0	0.0	10.0
Total revenues	1,079.3	1,015.9	3,207.1	2,980.2
Total segment expenses	920.6	893.0	2,784.8	2,632.3
Insurance policy benefits - fair value changes in embedded derivative liabilities	(2.9)	(12.1)	9.8	47.0
Amortization related to fair value changes in embedded derivative liabilities	0.6	2.7	(1.8)	(10.4)
Amortization related to net realized investment gains	0.7	0.2	1.0	0.9
Expenses related to VIEs	17.0	13.7	44.8	40.5
Fair value changes and amendment related to agent deferred compensation plan	13.4	(6.3)	13.4	12.0
Loss on reinsurance transaction	0.0	75.4	0.0	75.4
Expenses related to transition and support services agreements	0.0	0.0	0.0	10.0
Total benefits and expenses	949.4	966.6	2,852.0	2,807.7
Income before income taxes	129.9	49.3	355.1	172.5
Tax expense on period income	44.1	16.9	123.6	61.7
Valuation allowance for deferred tax assets and other tax items	(15.0)	13.8	(15.0)	(13.2)
Net income	100.8	18.6	246.5	124.0
Operating segments | Bankers Life:
Revenues:
Annuities	3.7	6.8	15.5	17.4
Health	307.2	310.3	926.9	933.3
Life	103.7	96.6	310.4	295.8
Net investment income	270.6	244.7	800.4	686.8
Fee revenue and other income	11.3	9.6	32.5	23.5
Total revenues	696.5	668.0	2,085.7	1,956.8
Expenses:
Insurance policy benefits	437.2	427.1	1,307.7	1,240.9
Amortization	38.7	43.8	126.3	135.3
Interest expense on investment borrowings	5.3	3.5	14.3	9.4
Other operating costs and expenses	108.4	105.5	328.2	312.2
Total expenses	589.6	579.9	1,776.5	1,697.8
Pre-tax operating earnings	106.9	88.1	309.2	259.0
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	696.5	668.0	2,085.7	1,956.8
Total segment expenses	589.6	579.9	1,776.5	1,697.8
Operating segments | Washington National:
Revenues:
Annuities	0.5	1.2	1.6	2.3
Health	160.4	156.9	480.3	469.1
Life	6.5	6.3	20.1	18.6
Net investment income	68.0	67.1	201.9	191.3
Fee revenue and other income	0.3	0.4	0.8	1.0
Total revenues	235.7	231.9	704.7	682.3
Expenses:
Insurance policy benefits	144.7	144.5	436.7	422.0
Amortization	14.3	14.3	43.9	44.5
Interest expense on investment borrowings	1.7	0.9	4.5	2.5
Other operating costs and expenses	47.5	47.0	145.0	140.3
Total expenses	208.2	206.7	630.1	609.3
Pre-tax operating earnings	27.5	25.2	74.6	73.0
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	235.7	231.9	704.7	682.3
Total segment expenses	208.2	206.7	630.1	609.3
Operating segments | Colonial Penn:
Revenues:
Health	0.5	0.6	1.6	2.0
Life	72.6	70.3	217.5	208.5
Net investment income	11.0	11.1	33.1	33.0
Fee revenue and other income	0.3	0.2	0.9	0.8
Total revenues	84.4	82.2	253.1	244.3
Expenses:
Insurance policy benefits	47.7	50.3	150.8	151.3
Amortization	3.9	3.7	11.9	11.3
Interest expense on investment borrowings	0.3	0.1	0.7	0.4
Other operating costs and expenses	23.5	27.2	73.0	84.2
Total expenses	75.4	81.3	236.4	247.2
Pre-tax operating earnings	9.0	0.9	16.7	(2.9)
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	84.4	82.2	253.1	244.3
Total segment expenses	75.4	81.3	236.4	247.2
Operating segments | Long-term care in run-off:
Revenues:
Health	4.2	0.0	13.3	0.0
Net investment income	6.8	0.0	26.5	0.0
Total revenues	11.0	0.0	39.8	0.0
Expenses:
Insurance policy benefits	11.4	0.0	36.6	0.0
Other operating costs and expenses	0.6	0.0	2.1	0.0
Total expenses	12.0	0.0	38.7	0.0
Pre-tax operating earnings	(1.0)	0.0	1.1	0.0
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	11.0	0.0	39.8	0.0
Total segment expenses	12.0	0.0	38.7	0.0
Corporate
Revenues:
Net investment income	7.0	6.7	24.8	16.6
Fee revenue and other income	1.8	2.5	6.5	7.6
Total revenues	8.8	9.2	31.3	24.2
Expenses:
Interest expense on corporate debt	11.7	11.5	34.8	34.3
Other operating costs and expenses	23.7	13.6	68.3	43.7
Total expenses	35.4	25.1	103.1	78.0
Pre-tax operating earnings	(26.6)	(15.9)	(71.8)	(53.8)
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total segment revenues	8.8	9.2	31.3	24.2
Total segment expenses	$ 35.4	$ 25.1	$ 103.1	$ 78.0