Fair Value Measurements - Quantitative Information About Unobservable Inputs, Including Disposal Groups (Details) - Recurring - Significant Unobservable Inputs (Level 3) $ in Millions	Dec. 31, 2024 USD ($)
Debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, including held for sale assets	$ 417
Corporate \| Securities Priced by the Company
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, including held for sale assets	$ 373
Corporate \| Securities Priced by the Company \| Minimum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment, including held for sale assets	0.0060
Corporate \| Securities Priced by the Company \| Maximum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment, including held for sale assets	0.1520
Corporate \| Securities Priced by the Company \| Weighted Average \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment, including held for sale assets	0.0370
Mortgage and other asset-backed securities \| Securities Priced by the Company
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, including held for sale assets	$ 43
Mortgage and other asset-backed securities \| Securities Priced by the Company \| Minimum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment, including held for sale assets	0.0100
Mortgage and other asset-backed securities \| Securities Priced by the Company \| Maximum \| Liquidity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Adjustment, including held for sale assets	0.0550
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, including held for sale assets	0.0280