Financial Guarantee Insurance Contracts Earned Premiums by Geographic Location (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 11	$ 11	$ 25	$ 21

Amount, after premiums ceded to other entities and premiums assumed by the entity, of financial guarantee premiums earned.

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