Reserve for Future Policy Benefits and Contractholder Funds - Schedule of Rollforward of Reserve for Future Policy Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Present value of expected net premiums
Beginning balance			$ 718	$ 2,013
Add: Classified as liabilities held for sale			1,584	0
Total beginning balance	$ 2,302	$ 2,013
Beginning balance at original discount rate	2,367	2,067
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(8)	(33)
Adjusted beginning balance			2,359	2,034
Issuances	291	262
Interest accrual	26	23
Net premiums collected	(127)	(114)
Ending balance at original discount rate	2,549	2,205
Effect of changes in discount rate assumptions	(64)	(90)
Less: Liabilities held for sale	(1,388)	0
Ending balance	1,097	2,115
Present value of expected future policy benefits
Beginning balance			770	3,110
Add: Classified as liabilities held for sale			2,628	0
Total beginning balance	3,398	3,110
Beginning balance at original discount rate	3,485	3,151
Effect of changes in cash flow assumptions			4	(6)
Effect of actual variances from expected experience			(14)	(39)
Adjusted beginning balance			3,475	3,106
Issuances	295	263
Interest accrual	40	34
Benefit payments	(119)	(114)
Ending balance at original discount rate	3,691	3,289
Effect of changes in discount rate assumptions	(91)	(108)
Less: Liabilities held for sale	(2,439)	0
Ending balance	1,161	3,181
Net reserve for future policy benefits	64	1,066
Less: reinsurance recoverables	0	81
Net reserve for future policy benefits, after reinsurance recoverables	64	985
Reserves related to short-duration contracts	22	259
Beginning balance			718	2,013
Accident and health insurance
Present value of expected net premiums
Beginning balance			712	1,688
Add: Classified as liabilities held for sale			1,247	0
Total beginning balance	1,959	1,688
Beginning balance at original discount rate	2,013	1,737
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(9)	(44)
Adjusted beginning balance			2,004	1,693
Issuances	250	230
Interest accrual	22	18
Net premiums collected	(110)	(98)
Ending balance at original discount rate	2,166	1,843
Effect of changes in discount rate assumptions	(54)	(81)
Less: Liabilities held for sale	(1,022)	0
Ending balance	1,090	1,762
Present value of expected future policy benefits
Beginning balance			757	2,453
Add: Classified as liabilities held for sale			1,943	0
Total beginning balance	2,700	2,453
Beginning balance at original discount rate	2,758	2,495
Effect of changes in cash flow assumptions			4	(6)
Effect of actual variances from expected experience			(12)	(47)
Adjusted beginning balance			2,750	2,442
Issuances	252	230
Interest accrual	32	25
Benefit payments	(110)	(102)
Ending balance at original discount rate	2,924	2,595
Effect of changes in discount rate assumptions	(60)	(86)
Less: Liabilities held for sale	(1,716)	0
Ending balance	1,148	2,509
Net reserve for future policy benefits	58	747
Less: reinsurance recoverables	0	80
Net reserve for future policy benefits, after reinsurance recoverables	58	667
Beginning balance			712	1,688
Traditional life
Present value of expected net premiums
Beginning balance			6	325
Add: Classified as liabilities held for sale			337	0
Total beginning balance	343	325
Beginning balance at original discount rate	354	330
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			1	11
Adjusted beginning balance			355	341
Issuances	41	32
Interest accrual	4	5
Net premiums collected	(17)	(16)
Ending balance at original discount rate	383	362
Effect of changes in discount rate assumptions	(10)	(9)
Less: Liabilities held for sale	(366)	0
Ending balance	7	353
Present value of expected future policy benefits
Beginning balance			13	657
Add: Classified as liabilities held for sale			685	0
Total beginning balance	698	657
Beginning balance at original discount rate	727	656
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(2)	8
Adjusted beginning balance			725	664
Issuances	43	33
Interest accrual	8	9
Benefit payments	(9)	(12)
Ending balance at original discount rate	767	694
Effect of changes in discount rate assumptions	(31)	(22)
Less: Liabilities held for sale	(723)	0
Ending balance	13	672
Net reserve for future policy benefits	6	319
Less: reinsurance recoverables	0	1
Net reserve for future policy benefits, after reinsurance recoverables	$ 6	$ 318
Beginning balance			$ 6	$ 325