Long-Duration Insurance Contracts - Balances of and Changes in the LFPB (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits	$ 1,611.5	$ 1,622.8
Whole Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	229.1	223.2	$ 215.1
Beginning balance at original discount rate	263.2	247.1	245.9
Change in cash flow assumptions		6.3	13.8	$ 0.0
Actual variances from expected experience		0.3	3.2	3.8
Adjusted balance		269.8	264.1	249.7
Issuances	10.7	12.6	10.8
Interest accruals	8.4	7.6	7.2
Net premiums collected	(18.3)	(21.1)	(20.6)
Ending balance at original discount rate	270.6	263.2	247.1
Effect of changes in discount rate assumptions	(31.1)	(34.1)	(23.9)
Ending balance	239.5	229.1	223.2
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	504.3	522.0	493.6
Beginning balance at original discount rate	631.9	617.4	592.1	581.9
Changes in cash flow assumptions		5.9	13.7	(0.6)
Actual variances from expected experience		1.0	3.4	4.0
Adjusted balance		624.3	609.2	585.3
Issuances	10.7	12.6	10.7
Interest accruals	21.0	19.8	19.0
Benefit payments	(24.1)	(24.2)	(22.9)
Ending balance at original discount rate	631.9	617.4	592.1
Effect of changes in discount rate assumptions	(113.5)	(113.1)	(70.1)
Ending balance	518.4	504.3	522.0
Net liability for future policy benefits	278.8	275.2	298.8
Less: Reinsurance recoverable	(57.3)	(60.2)	(64.3)
Net liability for future policy benefits, after reinsurance recoverable	221.5	215.0	234.5
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	221.5	215.0	234.5
Term Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	245.9	240.0	234.7
Beginning balance at original discount rate	271.2	256.6	265.4
Change in cash flow assumptions		(16.5)	4.6	(16.8)
Actual variances from expected experience		(3.4)	(0.5)	(2.7)
Adjusted balance		251.3	260.7	245.9
Issuances	23.6	25.2	25.2
Interest accruals	11.1	10.7	10.3
Net premiums collected	(26.3)	(25.4)	(24.8)
Ending balance at original discount rate	259.7	271.2	256.6
Effect of changes in discount rate assumptions	(14.5)	(25.3)	(16.6)
Ending balance	245.2	245.9	240.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	377.8	370.1	347.0
Beginning balance at original discount rate	429.8	433.2	405.4	401.0
Changes in cash flow assumptions		(20.7)	5.6	(16.7)
Actual variances from expected experience		(4.4)	(1.0)	1.3
Adjusted balance		408.1	410.0	385.6
Issuances	23.8	25.5	25.8
Interest accruals	17.0	16.1	15.2
Benefit payments	(19.1)	(18.4)	(21.2)
Ending balance at original discount rate	429.8	433.2	405.4
Effect of changes in discount rate assumptions	(40.4)	(55.4)	(35.3)
Ending balance	389.3	377.8	370.1
Net liability for future policy benefits	144.1	131.8	130.2
Less: Reinsurance recoverable	(20.9)	(19.3)	(19.1)
Net liability for future policy benefits, after reinsurance recoverable	123.2	112.5	111.1
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	123.2	112.5	111.1
Experience Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	66.6	71.7	68.3
Beginning balance at original discount rate	65.4	67.0	65.5
Change in cash flow assumptions		0.7	1.5	3.7
Actual variances from expected experience		1.6	0.0	0.7
Adjusted balance		67.7	68.5	69.9
Issuances	0.0	0.0	0.0
Interest accruals	3.7	3.7	3.7
Net premiums collected	(6.9)	(6.8)	(6.6)
Ending balance at original discount rate	64.5	65.4	67.0
Effect of changes in discount rate assumptions	2.6	1.2	4.7
Ending balance	67.1	66.6	71.7
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	813.2	883.0	867.5
Beginning balance at original discount rate	763.3	782.8	797.5	805.2
Changes in cash flow assumptions		1.7	2.2	5.0
Actual variances from expected experience		3.4	0.2	1.1
Adjusted balance		787.9	799.9	811.3
Issuances	0.0	0.0	0.0
Interest accruals	45.7	46.7	47.4
Benefit payments	(70.3)	(63.8)	(61.2)
Ending balance at original discount rate	763.3	782.8	797.5
Effect of changes in discount rate assumptions	44.5	30.4	85.5
Ending balance	807.8	813.2	883.0
Net liability for future policy benefits	740.8	746.6	811.3
Less: Reinsurance recoverable	(0.8)	(0.9)	(1.0)
Net liability for future policy benefits, after reinsurance recoverable	740.0	745.7	810.3
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	740.0	745.7	810.3
Limited-Pay Whole Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	34.2	32.2	29.7
Beginning balance at original discount rate	36.8	33.9	32.4
Change in cash flow assumptions		0.4	2.2	(0.2)
Actual variances from expected experience		(0.2)	0.0	1.0
Adjusted balance		37.0	36.1	33.2
Issuances	2.5	4.0	4.3
Interest accruals	1.5	1.4	1.2
Net premiums collected	(4.5)	(4.7)	(4.8)
Ending balance at original discount rate	36.5	36.8	33.9
Effect of changes in discount rate assumptions	(1.5)	(2.6)	(1.7)
Ending balance	35.0	34.2	32.2
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	86.2	89.6	79.4
Beginning balance at original discount rate	118.1	114.3	105.6	98.6
Changes in cash flow assumptions		0.2	2.4	(0.2)
Actual variances from expected experience		0.0	0.0	1.0
Adjusted balance		114.5	108.0	99.4
Issuances	2.5	4.0	4.3
Interest accruals	4.5	4.2	3.9
Benefit payments	(3.4)	(1.9)	(2.0)
Ending balance at original discount rate	118.1	114.3	105.6
Effect of changes in discount rate assumptions	(28.5)	(28.1)	(16.0)
Ending balance	89.6	86.2	89.6
Net liability for future policy benefits	54.6	52.1	57.4
Less: Reinsurance recoverable	(1.4)	(1.4)	(1.2)
Net liability for future policy benefits, after reinsurance recoverable	53.2	50.7	56.2
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	53.2	50.7	56.2
Supplemental Health
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	179.9	182.0	167.4
Beginning balance at original discount rate	214.6	213.4	205.1
Change in cash flow assumptions		(2.8)	(5.2)	6.5
Actual variances from expected experience		(2.4)	2.9	(1.6)
Adjusted balance		209.4	211.1	210.0
Issuances	22.9	20.9	19.4
Interest accruals	7.0	6.8	6.0
Net premiums collected	(25.7)	(24.2)	(22.0)
Ending balance at original discount rate	213.6	214.6	213.4
Effect of changes in discount rate assumptions	(26.1)	(34.7)	(31.4)
Ending balance	187.5	179.9	182.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	383.4	427.6	431.7
Beginning balance at original discount rate	462.7	482.8	517.9	537.1
Changes in cash flow assumptions		(5.3)	(6.5)	8.9
Actual variances from expected experience		(4.7)	2.5	(2.4)
Adjusted balance		472.8	513.9	543.6
Issuances	22.9	20.9	19.4
Interest accruals	13.9	14.4	14.4
Benefit payments	(46.9)	(66.4)	(59.5)
Ending balance at original discount rate	462.7	482.8	517.9
Effect of changes in discount rate assumptions	(83.7)	(99.4)	(90.3)
Ending balance	379.0	383.4	427.6
Net liability for future policy benefits	191.8	203.5	245.6
Less: Reinsurance recoverable	(5.1)	(4.7)	(4.0)
Net liability for future policy benefits, after reinsurance recoverable	186.7	198.8	241.6
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	186.7	198.8	241.6
Cancer
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits at December 31, 2025	66.0	72.2	92.7
Accident
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits at December 31, 2025	17.9	18.8	21.4
Disability
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits at December 31, 2025	21.3	21.4	23.5
Other
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits at December 31, 2025	81.5	86.4	104.0
SPIA (life contingent)
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	0.0	0.0	0.0
Beginning balance at original discount rate	0.0	0.0	0.0
Change in cash flow assumptions		0.0	0.0	0.0
Actual variances from expected experience		0.0	0.0	0.0
Adjusted balance		0.0	0.0	0.0
Issuances	2.4	2.8	5.6
Interest accruals	0.0	0.0	0.0
Net premiums collected	(2.4)	(2.8)	(5.6)
Ending balance at original discount rate	0.0	0.0	0.0
Effect of changes in discount rate assumptions	0.0	0.0	0.0
Ending balance	0.0	0.0	0.0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	97.3	104.2	103.3
Beginning balance at original discount rate	103.0	107.3	111.4	113.4
Changes in cash flow assumptions		0.0	0.0	0.0
Actual variances from expected experience		0.1	0.2	(0.8)
Adjusted balance		107.4	111.6	$ 112.6
Issuances	2.4	2.8	6.3
Interest accruals	4.1	4.3	4.4
Benefit payments	(10.9)	(11.4)	(11.9)
Ending balance at original discount rate	103.0	107.3	111.4
Effect of changes in discount rate assumptions	(7.0)	(10.0)	(7.2)
Ending balance	96.0	97.3	104.2
Net liability for future policy benefits	96.0	97.3	104.2
Less: Reinsurance recoverable	(3.8)	(3.5)	(3.6)
Net liability for future policy benefits, after reinsurance recoverable	92.2	93.8	100.6
Impact of flooring on net liability for future policy benefits	0.0	0.0	0.0
Net liability for future policy benefits at December 31, 2025	$ 92.2	$ 93.8	$ 100.6