Segment Information - Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2025 USD ($) segment	Mar. 31, 2024 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	2
Segment Reporting Information [Line Items]
Revenues	$ 345	$ 245
Segment loss and LAE (benefit)	40	(1)
Employee compensation and benefit expenses	60	58
Segment amortization of deferred acquisition cost	5	6
Segment expenses	169	125
Segment equity in earnings (losses) of investees	53	24
Less: Provision (benefit) for income taxes	44	31
Net investment income	87	84
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	16	16
Segment expenses	(2)	(5)
Segment equity in earnings (losses) of investees	(6)	(17)
Less: Provision (benefit) for income taxes	1	0
Operating Segments
Segment Reporting Information [Line Items]
Revenues	245	230
Segment expenses	68	85
Segment equity in earnings (losses) of investees	43	41
Less: Provision (benefit) for income taxes	40	36
Insurance | Operating Segments Excluding Intersegment Elimination
Segment Reporting Information [Line Items]
Revenues	237	227
Insurance | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	2	2
Insurance | Operating Segments
Segment Reporting Information [Line Items]
Revenues	239	229
Segment loss and LAE (benefit)	(23)	4
Employee compensation and benefit expenses	52	48
Segment amortization of deferred acquisition cost	5	6
Other segment items	30	27
Segment expenses	64	85
Segment equity in earnings (losses) of investees	30	40
Less: Provision (benefit) for income taxes	37	35
Segment adjusted operating income (loss)	168	149
Net investment income	86	83
Non-cash compensation and operating expenses	18	17
Asset Management | Operating Segments Excluding Intersegment Elimination
Segment Reporting Information [Line Items]
Revenues	5	1
Asset Management | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	1	0
Asset Management | Operating Segments
Segment Reporting Information [Line Items]
Revenues	6	1
Segment loss and LAE (benefit)	0	0
Employee compensation and benefit expenses	0	0
Segment amortization of deferred acquisition cost	0	0
Other segment items	4	0
Segment expenses	4	0
Segment equity in earnings (losses) of investees	13	1
Less: Provision (benefit) for income taxes	3	1
Segment adjusted operating income (loss)	12	1
Net investment income	0	0
Non-cash compensation and operating expenses	$ 0	$ 0