Reinsurance - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)	Oct. 01, 2023 agreement
Ceded Credit Risk [Line Items]
Number of reinsurance recoverable agreements | agreement				2
Investments	$ 138,737		$ 138,908
Fortitude Re
Ceded Credit Risk [Line Items]
Deposits assets	8,600		8,500
Investments	8,500		8,900
Fixed Annuities | Fortitude Re
Ceded Credit Risk [Line Items]
Reinsurance recoverables	10,500		10,600
Reinsurance recoverables on unpaid losses	2,500		2,500
Reinsurance recoverable amortization	24	$ 23
Deposits assets	$ 2,300		$ 2,400