Insurance Liabilities - Balances of Changes in Liability for Future Policy Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 11,054	$ 14,574
Effect of changes in discount rate assumptions (AOCI)	(1,865)	(2,200)
Reclassified to Liabilities held for sale	(4,247)		$ (4,287)
Beginning balance at original discount rate	17,206	16,774
Effect of changes in experience			(15)	$ 6
Adjusted beginning of year balance	17,191	16,780
Issuances	384	364
Interest accrual	139	129
Net premium collected	(548)	(446)
Foreign exchange impact	(137)	88
Other	(4)	3
Ending balance at original discount rate	17,025	16,918
Effect of changes in discount rate assumptions (AOCI)	(1,961)	(2,049)
Balance, end of period	10,817	14,869
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	60,386	57,886
Effect of changes in discount rate assumptions (AOCI)	5,658	7,672
Reclassified to Liabilities held for sale	(5,078)		(5,119)
Beginning balance at original discount rate	71,163	65,558
Effect of actual variances from expected experience			(25)	15
Adjusted beginning of year balance	71,138	65,573
Issuances	2,149	1,879
Interest accrual	737	648
Benefit payments	(1,292)	(1,182)
Foreign exchange impact	(262)	392
Other	(6)	(2)
Ending balance at original discount rate	72,464	67,308
Effect of changes in discount rate assumptions (AOCI)	6,982	6,470
Ending balance	60,404	60,838
Net liability for future policy benefits, end of period	49,587	45,969
Liability for future policy benefits for certain participating contracts	1,302	1,340
Liability for universal life policies with secondary guarantees and similar features	3,972	3,512
Deferred profit liability	2,553	2,396
Other reconciling items	1,571	1,629
Future policy benefits for life and accident and health insurance contracts	58,985	54,846	58,576
Less: Reinsurance recoverable	(22,898)	(24,266)
Liability for future policy benefits, end of period, net of Reinsurance recoverable	36,087	30,580
General Insurance
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	1,702	1,929
Effect of changes in discount rate assumptions (AOCI)	(339)	(262)
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	2,041	2,191
Effect of changes in experience			(2)	(10)
Adjusted beginning of year balance	2,039	2,181
Issuances	31	36
Interest accrual	11	11
Net premium collected	(138)	(57)
Foreign exchange impact	(91)	(8)
Other	0	0
Ending balance at original discount rate	1,852	2,163
Effect of changes in discount rate assumptions (AOCI)	(283)	(353)
Balance, end of period	1,569	1,810
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	2,149	2,380
Effect of changes in discount rate assumptions (AOCI)	441	362
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	2,590	2,742
Effect of actual variances from expected experience			(2)	(2)
Adjusted beginning of year balance	2,588	2,740
Issuances	32	36
Interest accrual	13	13
Benefit payments	(141)	(60)
Foreign exchange impact	(119)	(10)
Other	0	0
Ending balance at original discount rate	2,373	2,719
Effect of changes in discount rate assumptions (AOCI)	374	457
Ending balance	1,999	2,262
Net liability for future policy benefits, end of period	$ 430	$ 452
Weighted average liability duration of the liability for future policy benefits (in years)	9 years 1 month 6 days	10 years
Life and Retirement | Individual Retirement
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 0	$ 0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	0	0
Effect of changes in experience			0	1
Adjusted beginning of year balance	0	1
Issuances	0	6
Interest accrual	0	0
Net premium collected	0	(7)
Foreign exchange impact	0	0
Other	0	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
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	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 actual variances from expected experience			(6)	(3)
Adjusted beginning of year balance	1,479	1,387
Issuances	34	70
Interest accrual	16	12
Benefit payments	(33)	(32)
Foreign exchange impact	0	0
Other	0	0
Ending balance at original discount rate	1,496	1,437
Effect of changes in discount rate assumptions (AOCI)	153	141
Ending balance	1,343	1,296
Net liability for future policy benefits, end of period	$ 1,343	$ 1,296
Weighted average liability duration of the liability for future policy benefits (in years)	7 years 8 months 12 days	7 years 8 months 12 days
Life and Retirement | Group Retirement
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 0	$ 0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	0	0
Effect of changes in 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
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Balance, end of period	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	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 actual variances from expected experience			(1)	(1)
Adjusted beginning of year balance	213	212
Issuances	5	2
Interest accrual	3	3
Benefit payments	(7)	(7)
Foreign exchange impact	0	0
Other	0	0
Ending balance at original discount rate	214	210
Effect of changes in discount rate assumptions (AOCI)	0	(3)
Ending balance	214	213
Net liability for future policy benefits, end of period	$ 214	$ 213
Weighted average liability duration of the liability for future policy benefits (in years)	6 years 8 months 12 days	7 years 1 month 6 days
Life and Retirement | Life Insurance
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
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	(4,247)		(4,287)
Beginning balance at original discount rate	14,148	13,526
Effect of changes in experience			(13)	12
Adjusted beginning of year balance	14,135	13,538
Issuances	353	322
Interest accrual	117	106
Net premium collected	(381)	(352)
Foreign exchange impact	(46)	96
Other	(4)	3
Ending balance at original discount rate	14,174	13,713
Effect of changes in discount rate assumptions (AOCI)	(1,621)	(1,648)
Balance, end of period	8,306	12,065
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	17,531	21,179
Effect of changes in discount rate assumptions (AOCI)	2,745	3,424
Reclassified to Liabilities held for sale	(5,078)		(5,119)
Beginning balance at original discount rate	25,395	24,603
Effect of actual variances from expected experience			(7)	26
Adjusted beginning of year balance	25,388	24,629
Issuances	350	318
Interest accrual	236	224
Benefit payments	(458)	(476)
Foreign exchange impact	(61)	277
Other	(3)	1
Ending balance at original discount rate	25,452	24,973
Effect of changes in discount rate assumptions (AOCI)	3,149	3,081
Ending balance	17,225	21,892
Net liability for future policy benefits, end of period	$ 8,919	$ 9,827
Weighted average liability duration of the liability for future policy benefits (in years)	12 years 7 months 6 days	12 years 4 months 24 days
Life and Retirement | Institutional Markets
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 0	$ 0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	0	0
Effect of changes in 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
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Balance, end of period	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	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 actual variances from expected experience			0	(5)
Adjusted beginning of year balance	20,388	15,093
Issuances	1,726	1,450
Interest accrual	217	139
Benefit payments	(283)	(228)
Foreign exchange impact	(82)	125
Other	0	0
Ending balance at original discount rate	21,966	16,579
Effect of changes in discount rate assumptions (AOCI)	2,347	2,302
Ending balance	19,619	14,277
Net liability for future policy benefits, end of period	$ 19,619	$ 14,277
Weighted average liability duration of the liability for future policy benefits (in years)	12 years 2 months 12 days	11 years 6 months
Life and Retirement | Other
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 973	$ 991
Effect of changes in discount rate assumptions (AOCI)	(44)	(66)
Reclassified to Liabilities held for sale	0		0
Beginning balance at original discount rate	1,017	1,057
Effect of changes in experience			0	3
Adjusted beginning of year balance	1,017	1,060
Issuances	0	0
Interest accrual	11	12
Net premium collected	(29)	(30)
Foreign exchange impact	0	0
Other	0	0
Ending balance at original discount rate	999	1,042
Effect of changes in discount rate assumptions (AOCI)	(57)	(48)
Balance, end of period	942	994
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	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 actual variances from expected experience			$ (9)	$ 0
Adjusted beginning of year balance	21,082	21,512
Issuances	2	3
Interest accrual	252	257
Benefit payments	(370)	(379)
Foreign exchange impact	0	0
Other	(3)	(3)
Ending balance at original discount rate	20,963	21,390
Effect of changes in discount rate assumptions (AOCI)	959	492
Ending balance	20,004	20,898
Net liability for future policy benefits, end of period	$ 19,062	$ 19,904
Weighted average liability duration of the liability for future policy benefits (in years)	11 years 2 months 12 days	11 years 7 months 6 days