Future Policy Benefits - Balances of changes in liability for future policy benefits (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Present value of expected net premiums
Balance, beginning of year	$ 9,352	$ 12,645
Effect of changes in discount rate assumptions (AOCI)	1,526	1,938
Reclassified to Liabilities held-for-sale		(3,784)	$ (4,287)
Beginning balance at original discount rate	15,165	14,583
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
Issuances	733	986
Interest accrual	320	359
Net premium collected	(974)	(1,183)
Foreign exchange impact	(46)	44
Other	0	8
Dispositions	(5,108)
Ending balance at original discount rate	10,019	14,904
Effect of changes in discount rate assumptions (AOCI)	(491)	(2,294)
Balance, end of period	9,528	8,826
Present value of expected future policy benefits
Balance, beginning of year	58,237	55,506
Effect of changes in discount rate assumptions (AOCI)	5,217	7,310
Reclassified to Liabilities held-for-sale		4,352	5,119
Beginning balance at original discount rate	68,573	62,816
Effect of changes in cash flow assumptions			(104)	138
Effect of actual variances from expected experience			(41)	94
Adjusted beginning of year balance	68,428	63,048
Issuances	2,933	4,642
Interest accrual	2,112	1,973
Benefit payments	(3,333)	(3,507)
Foreign exchange impact	442	102
Other	(10)	(10)
Dispositions	(6,796)
Ending balance at original discount rate	63,776	66,248
Effect of changes in discount rate assumptions (AOCI)	(3,512)	(10,349)
Balance, end of period	60,264	51,547
Net liability for future policy benefits, end of period	50,736	42,721
Liability for future policy benefits for certain participating contracts	1,282	1,321
Liability for universal life policies	4,225	3,278
Deferred profit liability	2,597	2,400
Other reconciling items	576	635
Future policy benefits for life and accident and health insurance contracts	59,416	50,355	57,108
Less: Reinsurance recoverable:	22,418	21,121
Net liability for future policy benefits after reinsurance recoverable	36,998	29,234
Individual Retirement
Present value of expected net premiums
Balance, beginning of year	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held-for-sale			0
Beginning balance at original discount rate	0	0
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			0	0
Adjusted beginning of year balance	0	0
Issuances	0	0
Interest accrual	0	0
Net premium collected	0	0
Foreign exchange impact	0	0
Other	0	0
Dispositions	0
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Balance, end of period	0	0
Present value of expected future policy benefits
Balance, beginning of year	1,353	1,223
Effect of changes in discount rate assumptions (AOCI)	132	167
Reclassified to Liabilities held-for-sale		0	0
Beginning balance at original discount rate	1,485	1,390
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(27)	(1)
Adjusted beginning of year balance	1,458	1,389
Issuances	92	141
Interest accrual	50	38
Benefit payments	(105)	(95)
Foreign exchange impact	0	0
Other	0	0
Dispositions	0
Ending balance at original discount rate	1,495	1,473
Effect of changes in discount rate assumptions (AOCI)	(108)	(217)
Balance, end of period	1,387	1,256
Net liability for future policy benefits, end of period	1,387	1,256
Liability for future policy benefits for certain participating contracts	0	0
Liability for universal life policies	0	0
Deferred profit liability	59	80
Other reconciling items	34	34
Future policy benefits for life and accident and health insurance contracts	1,480	1,370
Less: Reinsurance recoverable:	5	4
Net liability for future policy benefits after reinsurance recoverable	$ 1,475	$ 1,366
Weighted average liability duration of the liability for future policy benefits (in years)	7 years 8 months 12 days	7 years 4 months 24 days
Group Retirement
Present value of expected net premiums
Balance, beginning of year	$ 0	$ 0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held-for-sale			0
Beginning balance at original discount rate	0	0
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			0	0
Adjusted beginning of year balance	0	0
Issuances	0	0
Interest accrual	0	0
Net premium collected	0	0
Foreign exchange impact	0	0
Other	0	0
Dispositions	0
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Balance, end of period	0	0
Present value of expected future policy benefits
Balance, beginning of year	217	211
Effect of changes in discount rate assumptions (AOCI)	(3)	2
Reclassified to Liabilities held-for-sale		0	0
Beginning balance at original discount rate	214	213
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			(2)	(1)
Adjusted beginning of year balance	212	212
Issuances	10	16
Interest accrual	9	8
Benefit payments	(18)	(20)
Foreign exchange impact	0	0
Other	(5)	0
Dispositions	0
Ending balance at original discount rate	208	216
Effect of changes in discount rate assumptions (AOCI)	5	(9)
Balance, end of period	213	207
Net liability for future policy benefits, end of period	213	207
Liability for future policy benefits for certain participating contracts	0	0
Liability for universal life policies	0	0
Deferred profit liability	11	9
Other reconciling items	0	0
Future policy benefits for life and accident and health insurance contracts	224	216
Less: Reinsurance recoverable:	0	0
Net liability for future policy benefits after reinsurance recoverable	$ 224	$ 216
Weighted average liability duration of the liability for future policy benefits (in years)	6 years 8 months 12 days	6 years 7 months 6 days
Life Insurance
Present value of expected net premiums
Balance, beginning of year	$ 8,379	$ 11,654
Effect of changes in discount rate assumptions (AOCI)	1,482	1,872
Reclassified to Liabilities held-for-sale		(3,784)	(4,287)
Beginning balance at original discount rate	14,148	13,526
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
Issuances	733	986
Interest accrual	288	325
Net premium collected	(888)	(1,093)
Foreign exchange impact	(46)	44
Other	0	11
Dispositions	(5,108)
Ending balance at original discount rate	9,074	13,869
Effect of changes in discount rate assumptions (AOCI)	(463)	(2,199)
Balance, end of period	8,611	7,886
Present value of expected future policy benefits
Balance, beginning of year	17,531	21,179
Effect of changes in discount rate assumptions (AOCI)	2,745	3,424
Reclassified to Liabilities held-for-sale		4,352	5,119
Beginning balance at original discount rate	25,395	24,603
Effect of changes in cash flow assumptions			(24)	62
Effect of actual variances from expected experience			15	85
Adjusted beginning of year balance	25,386	24,750
Issuances	721	978
Interest accrual	635	679
Benefit payments	(1,204)	(1,461)
Foreign exchange impact	(61)	54
Other	2	8
Dispositions	(6,796)
Ending balance at original discount rate	18,683	25,008
Effect of changes in discount rate assumptions (AOCI)	(825)	(4,397)
Balance, end of period	17,858	16,259
Net liability for future policy benefits, end of period	9,247	8,373
Liability for future policy benefits for certain participating contracts	12	13
Liability for universal life policies	4,170	3,223
Deferred profit liability	22	18
Other reconciling items	449	508
Future policy benefits for life and accident and health insurance contracts	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
Institutional Markets
Present value of expected net premiums
Balance, beginning of year	$ 0	$ 0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held-for-sale			0
Beginning balance at original discount rate	0	0
Effect of changes in cash flow assumptions			0	0
Effect of actual variances from expected experience			0	0
Adjusted beginning of year balance	0	0
Issuances	0	0
Interest accrual	0	0
Net premium collected	0	0
Foreign exchange impact	0	0
Other	0	0
Dispositions	0
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Balance, end of period	0	0
Present value of expected future policy benefits
Balance, beginning of year	18,482	12,464
Effect of changes in discount rate assumptions (AOCI)	1,906	2,634
Reclassified to Liabilities held-for-sale		0	0
Beginning balance at original discount rate	20,388	15,098
Effect of changes in cash flow assumptions			(41)	0
Effect of actual variances from expected experience			(8)	21
Adjusted beginning of year balance	20,339	15,119
Issuances	2,105	3,503
Interest accrual	665	478
Benefit payments	(907)	(810)
Foreign exchange impact	503	48
Other	0	0
Dispositions	0
Ending balance at original discount rate	22,705	18,338
Effect of changes in discount rate assumptions (AOCI)	(2,260)	(3,512)
Balance, end of period	20,445	14,826
Net liability for future policy benefits, end of period	20,445	14,826
Liability for future policy benefits for certain participating contracts	0	0
Liability for universal life policies	0	0
Deferred profit liability	1,673	1,428
Other reconciling items	0	0
Future policy benefits for life and accident and health insurance contracts	22,118	16,254
Less: Reinsurance recoverable:	41	37
Net liability for future policy benefits after reinsurance recoverable	$ 22,077	$ 16,217
Weighted average liability duration of the liability for future policy benefits (in years)	11 years 10 months 24 days	10 years 10 months 24 days
Corporate and Other
Present value of expected net premiums
Balance, beginning of year	$ 973	$ 991
Effect of changes in discount rate assumptions (AOCI)	44	66
Reclassified to Liabilities held-for-sale			0
Beginning balance at original discount rate	1,017	1,057
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
Issuances	0	0
Interest accrual	32	34
Net premium collected	(86)	(90)
Foreign exchange impact	0	0
Other	0	(3)
Dispositions	0
Ending balance at original discount rate	945	1,035
Effect of changes in discount rate assumptions (AOCI)	(28)	(95)
Balance, end of period	917	940
Present value of expected future policy benefits
Balance, beginning of year	20,654	20,429
Effect of changes in discount rate assumptions (AOCI)	437	1,083
Reclassified to Liabilities held-for-sale		0	0
Beginning balance at original discount rate	21,091	21,512
Effect of changes in cash flow assumptions			(39)	76
Effect of actual variances from expected experience			$ (19)	$ (10)
Adjusted beginning of year balance	21,033	21,578
Issuances	5	4
Interest accrual	753	770
Benefit payments	(1,099)	(1,121)
Foreign exchange impact	0	0
Other	(7)	(18)
Dispositions	0
Ending balance at original discount rate	20,685	21,213
Effect of changes in discount rate assumptions (AOCI)	(324)	(2,214)
Balance, end of period	20,361	18,999
Net liability for future policy benefits, end of period	19,444	18,059
Liability for future policy benefits for certain participating contracts	1,270	1,308
Liability for universal life policies	55	55
Deferred profit liability	832	865
Other reconciling items	93	93
Future policy benefits for life and accident and health insurance contracts	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