Future Policy Benefits - Schedule of liabilities by product (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Net liability for future policy benefits, beginning balance	$ 57,108
Effect of changes in cash flow assumptions			$ (68)	$ 55
Effect of actual variances from expected experience			(3)	52
Adjusted beginning of year balance			15,094	14,690
Interest accrual	320	$ 359
Other	0	8
Net liability for future policy benefits, end of period	59,416	50,355
Less: Reinsurance recoverable:	(22,418)	(21,121)
Net liability for future policy benefits after reinsurance recoverable	36,998	29,234
Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Net liability for future policy benefits, beginning balance	3,786	3,355
Effect of changes in cash flow assumptions			38	(41)
Effect of actual variances from expected experience			271	171
Adjusted beginning of year balance			4,095	3,485
Assessments	435	519
Excess benefits paid	(646)	(681)
Interest accrual	121	97
Other	(8)	20
Changes related to unrealized appreciation (depreciation) of investments	228	(162)
Net liability for future policy benefits, end of period	4,225	3,278
Less: Reinsurance recoverable:	(210)	(162)
Net liability for future policy benefits after reinsurance recoverable	4,015	3,116
Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Effect of changes in cash flow assumptions			(57)	34
Effect of actual variances from expected experience			4	36
Adjusted beginning of year balance			14,095	13,596
Interest accrual	288	325
Other	0	11
Net liability for future policy benefits, end of period	13,900	12,135
Less: Reinsurance recoverable:	(678)	(700)
Net liability for future policy benefits after reinsurance recoverable	$ 13,222	$ 11,435
Weighted average liability duration of the liability for future policy benefits (in years)	11 years 1 month 6 days	11 years 10 months 24 days
Life Insurance | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Net liability for future policy benefits, beginning balance	$ 3,731	$ 3,300
Effect of changes in cash flow assumptions			38	(41)
Effect of actual variances from expected experience			274	174
Adjusted beginning of year balance			4,043	3,433
Assessments	434	518
Excess benefits paid	(646)	(681)
Interest accrual	119	95
Other	(8)	20
Changes related to unrealized appreciation (depreciation) of investments	228	(162)
Net liability for future policy benefits, end of period	4,170	3,223
Less: Reinsurance recoverable:	(155)	(162)
Net liability for future policy benefits after reinsurance recoverable	$ 4,015	$ 3,061
Weighted average liability duration of the liability for future policy benefits (in years)	24 years	25 years 4 months 24 days
Corporate and Other
Liability for Future Policy Benefit, Activity [Line Items]
Effect of changes in cash flow assumptions			(11)	21
Effect of actual variances from expected experience			(7)	16
Adjusted beginning of year balance			999	1,094
Interest accrual	$ 32	$ 34
Other	0	(3)
Net liability for future policy benefits, end of period	21,694	20,380
Less: Reinsurance recoverable:	(21,694)	(20,380)
Net liability for future policy benefits after reinsurance recoverable	$ 0	$ 0
Weighted average liability duration of the liability for future policy benefits (in years)	11 years 2 months 12 days	10 years 9 months 18 days
Corporate and Other | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Net liability for future policy benefits, beginning balance	$ 55	$ 55
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(3)	(3)
Adjusted beginning of year balance			$ 52	$ 52
Assessments	1	1
Excess benefits paid	0	0
Interest accrual	2	2
Other	0	0
Changes related to unrealized appreciation (depreciation) of investments	0	0
Net liability for future policy benefits, end of period	55	55
Less: Reinsurance recoverable:	(55)	0
Net liability for future policy benefits after reinsurance recoverable	$ 0	$ 55
Weighted average liability duration of the liability for future policy benefits (in years)	9 years	9 years 3 months 18 days