Insurance Liabilities - Balances of changes in liability for future policy benefits (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 14,574	$ 15,643
Effect of changes in discount rate assumptions (AOCI)	2,200	(856)
Beginning balance at original discount rate	16,774	14,787
Effect of changes in cash flow assumptions			$ 55	$ 123
Effect of actual variances from expected experience			8	(14)
Adjusted beginning of year balance	16,837	14,896
Issuances	1,086	1,050
Interest accrual	381	334
Net premium collected	(1,343)	(1,153)
Foreign exchange impact	(18)	(854)
Other	(55)	(1)
Ending balance at original discount rate	16,888	14,272
Effect of changes in discount rate assumptions (AOCI)	(2,648)	(2,191)
Reclassified to Liabilities held for sale	(3,784)
Balance, end of period	10,456	12,081
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	57,886	70,643
Effect of changes in discount rate assumptions (AOCI)	7,672	(9,401)
Beginning balance at original discount rate	65,558	61,242
Adjustments			138	134
Effect of actual variances from expected experience			51	(77)
Adjusted beginning of year balance	65,747	61,299
Issuances	4,746	2,735
Interest accrual	2,000	1,815
Benefit payments	(3,660)	(3,141)
Foreign exchange impact	9	(1,648)
Other	(84)	(13)
Ending balance at original discount rate	68,758	61,047
Effect of changes in discount rate assumptions (AOCI)	(10,810)	(8,368)
Reclassified to Liabilities held for sale	(4,352)
Ending balance	53,596	52,679
Net liability for future policy benefits, end of period	43,140	40,598
Liability for future policy benefits for certain participating contracts	1,321	1,363
Liability for universal life policies with secondary guarantees and similar features	3,278	3,232
Deferred profit liability	2,401	2,164
Other reconciling items	1,526	1,980
Future policy benefits for life and accident and health insurance contracts	51,666	49,337	51,914		$ 67,364
Less: Reinsurance recoverable:	(21,833)	(24,307)
Net liability for future policy benefits after reinsurance recoverable	29,833	25,030
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
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
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0
Balance, end of period	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	1,223	1,373
Effect of changes in discount rate assumptions (AOCI)	167	(95)
Beginning balance at original discount rate	1,390	1,278
Adjustments			0	0
Effect of actual variances from expected experience			(1)	(16)
Adjusted beginning of year balance	1,389	1,262
Issuances	141	156
Interest accrual	38	31
Benefit payments	(95)	(86)
Foreign exchange impact	0	0
Other	0	0
Ending balance at original discount rate	1,473	1,363
Effect of changes in discount rate assumptions (AOCI)	(217)	(188)
Reclassified to Liabilities held for sale	0
Ending balance	1,256	1,175
Net liability for future policy benefits, end of period	$ 1,256	$ 1,175
Weighted average liability duration of the liability for future policy benefits (in years)	7 years 4 months 24 days	7 years 4 months 24 days
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
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
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0
Balance, end of period	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	211	264
Effect of changes in discount rate assumptions (AOCI)	2	(46)
Beginning balance at original discount rate	213	218
Adjustments			0	0
Effect of actual variances from expected experience			(1)	(2)
Adjusted beginning of year balance	212	216
Issuances	16	9
Interest accrual	8	7
Benefit payments	(20)	(18)
Foreign exchange impact	0	0
Other	0	0
Ending balance at original discount rate	216	214
Effect of changes in discount rate assumptions (AOCI)	(9)	(4)
Reclassified to Liabilities held for sale	0
Ending balance	207	210
Net liability for future policy benefits, end of period	$ 207	$ 210
Weighted average liability duration of the liability for future policy benefits (in years)	6 years 7 months 6 days	6 years 9 months 18 days
Life Insurance
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 11,654	$ 14,369
Effect of changes in discount rate assumptions (AOCI)	1,872	(706)
Beginning balance at original discount rate	13,526	13,663
Effect of changes in cash flow assumptions			34	123
Effect of actual variances from expected experience			36	(19)
Adjusted beginning of year balance	13,596	13,767
Issuances	986	1,050
Interest accrual	325	297
Net premium collected	(1,093)	(1,060)
Foreign exchange impact	44	(854)
Other	11	(1)
Ending balance at original discount rate	13,869	13,199
Effect of changes in discount rate assumptions (AOCI)	(2,199)	(2,111)
Reclassified to Liabilities held for sale	3,784
Balance, end of period	7,886	11,088
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	21,179	27,442
Effect of changes in discount rate assumptions (AOCI)	3,424	(2,717)
Beginning balance at original discount rate	24,603	24,725
Adjustments			62	140
Effect of actual variances from expected experience			85	(24)
Adjusted beginning of year balance	24,750	24,841
Issuances	978	1,055
Interest accrual	679	657
Benefit payments	(1,461)	(1,317)
Foreign exchange impact	54	(1,093)
Other	8	(2)
Ending balance at original discount rate	25,008	24,141
Effect of changes in discount rate assumptions (AOCI)	(4,397)	(3,844)
Reclassified to Liabilities held for sale	4,352
Ending balance	16,259	20,297
Net liability for future policy benefits, end of period	$ 8,373	$ 9,209
Weighted average liability duration of the liability for future policy benefits (in years)	11 years 10 months 24 days	11 years 10 months 24 days
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
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
Ending balance at original discount rate	0	0
Effect of changes in discount rate assumptions (AOCI)	0	0
Reclassified to Liabilities held for sale	0
Balance, end of period	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	12,464	13,890
Effect of changes in discount rate assumptions (AOCI)	2,634	(870)
Beginning balance at original discount rate	15,098	13,020
Adjustments			0	(6)
Effect of actual variances from expected experience			21	(11)
Adjusted beginning of year balance	15,119	13,003
Issuances	3,503	1,507
Interest accrual	478	333
Benefit payments	(810)	(602)
Foreign exchange impact	48	(555)
Other	0	0
Ending balance at original discount rate	18,338	13,686
Effect of changes in discount rate assumptions (AOCI)	(3,512)	(2,786)
Reclassified to Liabilities held for sale	0
Ending balance	14,826	10,900
Net liability for future policy benefits, end of period	$ 14,826	$ 10,900
Weighted average liability duration of the liability for future policy benefits (in years)	10 years 10 months 24 days	10 years 1 month 6 days
Other Operations before consolidation and eliminations
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 991	$ 1,274
Effect of changes in discount rate assumptions (AOCI)	66	(150)
Beginning balance at original discount rate	1,057	1,124
Effect of changes in cash flow assumptions			21	0
Effect of actual variances from expected experience			16	5
Adjusted beginning of year balance	1,094	1,129
Issuances	0	0
Interest accrual	34	37
Net premium collected	(90)	(93)
Foreign exchange impact	0	0
Other	(3)	0
Ending balance at original discount rate	1,035	1,073
Effect of changes in discount rate assumptions (AOCI)	(95)	(80)
Reclassified to Liabilities held for sale	0
Balance, end of period	940	993
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	20,429	27,674
Effect of changes in discount rate assumptions (AOCI)	1,083	(5,673)
Beginning balance at original discount rate	21,512	22,001
Adjustments			76	0
Effect of actual variances from expected experience			(10)	$ (24)
Adjusted beginning of year balance	21,578	21,977
Issuances	4	8
Interest accrual	770	787
Benefit payments	(1,121)	(1,118)
Foreign exchange impact	0	0
Other	(18)	(11)
Ending balance at original discount rate	21,213	21,643
Effect of changes in discount rate assumptions (AOCI)	(2,214)	(1,546)
Reclassified to Liabilities held for sale	0
Ending balance	18,999	20,097
Net liability for future policy benefits, end of period	$ 18,059	$ 19,104
Weighted average liability duration of the liability for future policy benefits (in years)	10 years 9 months 18 days	11 years 2 months 12 days
General Insurance
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year	$ 1,929
Effect of changes in discount rate assumptions (AOCI)	262
Beginning balance at original discount rate	2,191
Effect of changes in cash flow assumptions			0
Effect of actual variances from expected experience			(44)
Adjusted beginning of year balance	2,147
Issuances	100
Interest accrual	22
Net premium collected	(160)
Foreign exchange impact	(62)
Other	(63)
Ending balance at original discount rate	1,984
Effect of changes in discount rate assumptions (AOCI)	(354)
Reclassified to Liabilities held for sale	0
Balance, end of period	1,630
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	2,380
Effect of changes in discount rate assumptions (AOCI)	362
Beginning balance at original discount rate	2,742
Adjustments			0
Effect of actual variances from expected experience			$ (43)
Adjusted beginning of year balance	2,699
Issuances	104
Interest accrual	27
Benefit payments	(153)
Foreign exchange impact	(93)
Other	(74)
Ending balance at original discount rate	2,510
Effect of changes in discount rate assumptions (AOCI)	(461)
Reclassified to Liabilities held for sale	0
Ending balance	2,049
Net liability for future policy benefits, end of period	$ 419
Weighted average liability duration of the liability for future policy benefits (in years)	9 years 6 months