Market Risk Benefits - Balances and changes in market risk benefits (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Market Risk Benefit [Line Items]
Market risk benefit	$ 3,612	$ 4,034	$ 3,990	$ 7,034		$ 8,401
Market risk benefit in an asset position						176
Reinsured market risk benefit						162
Market risk benefit assets, at fair value	978	796			$ 338	338
Market risk benefit liabilities, at fair value	4,519	4,736			8,739	8,739
As Previously Reported
Market Risk Benefit [Line Items]
Market risk benefit						0
Market risk benefit assets, at fair value		0			0
Market risk benefit liabilities, at fair value		0			$ 0
Adjustment for the reclassification of the embedded derivative liability from policyholder contract deposits, net of the host adjustment
Market Risk Benefit [Line Items]
Market risk benefit						6,247
Adjustment for the reclassification of additional liabilities from Future policy benefits
Market Risk Benefit [Line Items]
Market risk benefit						1,609
Adjustments for the cumulative effect of the changes to our own credit risk between the original contract issuance date and the transition date
Market Risk Benefit [Line Items]
Market risk benefit						2,327
Adjustment for the removal of related balances in Accumulated other comprehensive income (loss) originating from unrealized gains (losses)
Market Risk Benefit [Line Items]
Market risk benefit						(605)
Adjustment for the remaining difference (exclusive of our own credit risk change and host contract adjustments) between previous carrying amount and fair value measurement for the MRB
Market Risk Benefit [Line Items]
Market risk benefit						(1,177)
Individual Retirement
Market Risk Benefit [Line Items]
Market risk benefit	3,396	3,738	3,693	6,452		7,599
Market risk benefit in an asset position						176
Reinsured market risk benefit						162
Market risk benefit assets, at fair value						338
Market risk benefit liabilities, at fair value						7,937
Individual Retirement | As Previously Reported
Market Risk Benefit [Line Items]
Market risk benefit						0
Individual Retirement | Adjustment for the reclassification of the embedded derivative liability from policyholder contract deposits, net of the host adjustment
Market Risk Benefit [Line Items]
Market risk benefit						5,671
Individual Retirement | Adjustment for the reclassification of additional liabilities from Future policy benefits
Market Risk Benefit [Line Items]
Market risk benefit						1,388
Individual Retirement | Adjustments for the cumulative effect of the changes to our own credit risk between the original contract issuance date and the transition date
Market Risk Benefit [Line Items]
Market risk benefit						2,140
Individual Retirement | Adjustment for the removal of related balances in Accumulated other comprehensive income (loss) originating from unrealized gains (losses)
Market Risk Benefit [Line Items]
Market risk benefit						(516)
Individual Retirement | Adjustment for the remaining difference (exclusive of our own credit risk change and host contract adjustments) between previous carrying amount and fair value measurement for the MRB
Market Risk Benefit [Line Items]
Market risk benefit						(1,084)
Group Retirement
Market Risk Benefit [Line Items]
Market risk benefit	$ 216	$ 296	$ 297	$ 582		802
Market risk benefit in an asset position						0
Reinsured market risk benefit						0
Market risk benefit assets, at fair value						0
Market risk benefit liabilities, at fair value						802
Group Retirement | As Previously Reported
Market Risk Benefit [Line Items]
Market risk benefit						0
Group Retirement | Adjustment for the reclassification of the embedded derivative liability from policyholder contract deposits, net of the host adjustment
Market Risk Benefit [Line Items]
Market risk benefit						576
Group Retirement | Adjustment for the reclassification of additional liabilities from Future policy benefits
Market Risk Benefit [Line Items]
Market risk benefit						221
Group Retirement | Adjustments for the cumulative effect of the changes to our own credit risk between the original contract issuance date and the transition date
Market Risk Benefit [Line Items]
Market risk benefit						187
Group Retirement | Adjustment for the removal of related balances in Accumulated other comprehensive income (loss) originating from unrealized gains (losses)
Market Risk Benefit [Line Items]
Market risk benefit						(89)
Group Retirement | Adjustment for the remaining difference (exclusive of our own credit risk change and host contract adjustments) between previous carrying amount and fair value measurement for the MRB
Market Risk Benefit [Line Items]
Market risk benefit						$ (93)