Insurance Liabilities - Schedule of liabilities by product (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts	$ 51,666	$ 49,337	$ 51,914		$ 67,364
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
Other	(55)	(1)
Less: Reinsurance recoverable:	(21,833)	(24,307)
Net liability for future policy benefits after reinsurance recoverable	29,833	25,030
As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts			59,223		$ 56,878
Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts	3,278	3,232	3,355	5,007		$ 5,172
Effect of changes in cash flow assumptions			(41)	(24)
Effect of actual variances from expected experience			171	242
Adjusted beginning of year balance			3,485	5,225
Assessments	519	529
Excess benefits paid	(681)	(697)
Interest accrual	97	96
Other	20	(14)
Changes related to unrealized appreciation (depreciation) of investments	(162)	(1,907)
Less: Reinsurance recoverable:	(162)	(214)
Net liability for future policy benefits after reinsurance recoverable	3,116	3,018
Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						6,816
Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(1,039)
Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(605)
Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
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
Other	$ 11	$ (1)
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
Life Insurance | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts	$ 3,223	$ 3,177	3,300	4,952		5,117
Effect of changes in cash flow assumptions			(41)	(24)
Effect of actual variances from expected experience			174	245
Adjusted beginning of year balance			3,433	5,173
Assessments	518	528
Excess benefits paid	(681)	(697)
Interest accrual	95	94
Other	20	(14)
Changes related to unrealized appreciation (depreciation) of investments	(162)	(1,907)
Less: Reinsurance recoverable:	(162)	(214)
Net liability for future policy benefits after reinsurance recoverable	$ 3,061	$ 2,963
Weighted average liability duration of the liability for future policy benefits (in years)	25 years 4 months 24 days	26 years 9 months 18 days
Life Insurance | Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						5,117
Life Insurance | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Life Insurance | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Individual Retirement
Liability for Future Policy Benefit, Activity [Line Items]
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
Other	$ 0	$ 0
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
Individual Retirement | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Individual Retirement | Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						1,423
Individual Retirement | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(907)
Individual Retirement | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(516)
Group Retirement
Liability for Future Policy Benefit, Activity [Line Items]
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
Other	$ 0	$ 0
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
Group Retirement | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Group Retirement | Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						221
Group Retirement | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(132)
Group Retirement | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						(89)
Institutional Markets | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Institutional Markets | Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Institutional Markets | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Institutional Markets | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Other Operations before consolidation and eliminations
Liability for Future Policy Benefit, Activity [Line Items]
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
Other	$ (3)	$ 0
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
Other Operations before consolidation and eliminations | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts	$ 55	$ 55	55	55		55
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
Less: Reinsurance recoverable:	0	0
Net liability for future policy benefits after reinsurance recoverable	$ 55	$ 55
Weighted average liability duration of the liability for future policy benefits (in years)	9 years 3 months 18 days	9 years 7 months 6 days
Other Operations before consolidation and eliminations | Universal Life | As Previously Reported
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						55
Other Operations before consolidation and eliminations | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						0
Other Operations before consolidation and eliminations | Universal Life | Effect Of Application Of Accounting Standards Update 2018-12, Adjustments To Reclass URGL Impacts To Market Risk Benefits
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits for life and accident and health insurance contracts						$ 0