Derivative Instruments - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative assets by counterparty	$ 108	$ 117
Derivative assets, held collateral	92	841
Derivative liabilities by counterparty	1,183	937
Derivative liabilities, held collateral	1,382	751
Derivative disbursement obligation	0	910
Derivative claim	215	0
Derivative asset, pledged collateral	2,294	2,616
Embedded derivatives
Derivative [Line Items]
Net fair value, derivative asset (liability)	(2,568)	(2,090)
Derivatives related to funds withheld under reinsurance treaties
Derivative [Line Items]
Net fair value, derivative asset (liability)	2,530	2,483
Funds withheld embedded derivative | Derivatives related to funds withheld under reinsurance treaties
Derivative [Line Items]
Net fair value, derivative asset (liability)	$ 2,496	$ 2,468