Fair Value Measurements - Quantitative Information About Unobservable Inputs (Details) - Recurring - Significant Unobservable Inputs (Level 3) $ in Millions	Jun. 30, 2026 USD ($)	Dec. 31, 2025 USD ($)
Debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 296	$ 325
Corporate \| Securities Priced by the Company
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 262	$ 286
Corporate \| Securities Priced by the Company \| Minimum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0060	0.0060
Corporate \| Securities Priced by the Company \| Maximum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0920	0.0920
Corporate \| Securities Priced by the Company \| Weighted Average \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0140	0.0175
Mortgage and other asset-backed securities \| Securities Priced by the Company
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 33	$ 38
Mortgage and other asset-backed securities \| Securities Priced by the Company \| Minimum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0115	0.0105
Mortgage and other asset-backed securities \| Securities Priced by the Company \| Maximum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0350	0.0350
Mortgage and other asset-backed securities \| Securities Priced by the Company \| Weighted Average \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment	0.0160	0.0160
Other debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 1	$ 1