Reinsurance - Rollforward of the reinsurable allowance for credit losses before adoption (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Jan. 01, 2021	Dec. 31, 2020
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				$ 3,176
Fortitude RE
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes	$ 28,895	$ 30,751	$ 42,244	36,801
Excluding Fortitude
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes	$ 38,163	38,971	39,432	36,300
As Previously Reported
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				2,707
As Previously Reported | Fortitude RE
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes		32,159	34,578	29,135
As Previously Reported | Excluding Fortitude
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes		$ 39,434	$ 38,963
Reclassification of cost of reinsurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				416
Reclassification to Market risk benefits
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				(35)
Adjustments for NPR* > 100%
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				9
Adjustments for NPR* > 100% | Fortitude RE
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				55
Change due to the current upper-medium grade discount rate
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				79
Change due to the current upper-medium grade discount rate | Fortitude RE
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				7,611
Individual Retirement
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				274
Individual Retirement | As Previously Reported
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				309
Individual Retirement | Reclassification of cost of reinsurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Individual Retirement | Reclassification to Market risk benefits
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				(35)
Individual Retirement | Adjustments for NPR* > 100%
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Individual Retirement | Change due to the current upper-medium grade discount rate
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Life Insurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				2,869
Life Insurance | As Previously Reported
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				2,370
Life Insurance | Reclassification of cost of reinsurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				416
Life Insurance | Reclassification to Market risk benefits
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Life Insurance | Adjustments for NPR* > 100%
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				9
Life Insurance | Change due to the current upper-medium grade discount rate
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				74
Institutional Markets
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				33
Institutional Markets | As Previously Reported
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				28
Institutional Markets | Reclassification of cost of reinsurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Institutional Markets | Reclassification to Market risk benefits
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Institutional Markets | Adjustments for NPR* > 100%
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				0
Institutional Markets | Change due to the current upper-medium grade discount rate
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				5
General Insurance
Effects of Reinsurance [Line Items]
Reinsurance assets, net of allowance for credit losses and disputes				$ 5,400