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Contracts Accounted for as Credit Derivatives - Net Change in Fair Value of Credit Derivatives Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Realized gains (losses) and other settlements	$ 2	$ 2	$ 107	$ 2
Net unrealized gains (losses)	3	1	3	17
Fair value gains (losses) on credit derivatives	$ 5	$ 3	$ 110	$ 19

X

- Definition

Represents the premiums received and receivable, ceding commissions, and the losses paid and payable. This element refers to the gain (loss) included in earnings.

+ References

No definition available.

+ Details

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X

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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- References

No definition available.

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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