Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) - Discounted cash flow $ in Millions	Mar. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fixed maturity securities	$ 1,981	$ 1,927
Credit spread \| Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Debt securities, available-for-sale, measurement Input	0.01	0.01
Credit spread \| Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Debt securities, available-for-sale, measurement Input	0.11	0.11
Credit spread \| Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Debt securities, available-for-sale, measurement Input	0.02	0.02

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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+ Details