Receivables from Policyholders - Allowance for Expected Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	$ 13.9	$ 13.1
Provision for Expected Credit Losses	39.6	41.6
Write-offs of Uncollectible Receivables from Policyholders	(50.6)	(40.8)
Balance at End of Year	2.9	13.9
Receivable Balance at End of Year	986.1	960.2
Receivable Balance	977.9	959.5
Variable Interest Entity, Primary Beneficiary
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	0.0
Balance at End of Year	0.0	0.0
Receivable Balance	8.2	0.7
Operating Segments
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	12.9	12.3
Provision for Expected Credit Losses	39.2	39.8
Write-offs of Uncollectible Receivables from Policyholders	(49.5)	(39.2)
Balance at End of Year	2.6	12.9
Receivable Balance at End of Year	973.9	886.7
Non-Core Operations
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	1.0	0.8
Provision for Expected Credit Losses	0.4	1.8
Write-offs of Uncollectible Receivables from Policyholders	(1.1)	(1.6)
Balance at End of Year	0.3	1.0
Receivable Balance at End of Year	12.2	73.5
Specialty | Operating Segments
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	12.9	12.3
Provision for Expected Credit Losses	38.9	39.3
Write-offs of Uncollectible Receivables from Policyholders	(49.2)	(38.7)
Balance at End of Year	2.6	12.9
Receivable Balance at End of Year	962.8	875.4
Life | Operating Segments
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	0.0	0.0
Provision for Expected Credit Losses	0.3	0.5
Write-offs of Uncollectible Receivables from Policyholders	(0.3)	(0.5)
Balance at End of Year	0.0	0.0
Receivable Balance at End of Year	$ 11.1	$ 11.3