The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

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

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Gross amount, as of the balance sheet date, due the entity from (a) agents and insureds, (b) uncollected premiums and (c) others, before deducting the allowance for doubtful accounts.

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The estimated amount as of the balance sheet date to be received by an insurer from the sale of property (usually damaged) on which the insurer has paid a total claim to the insured and has obtained title to the property and the right of an insurer to pursue any course of recovery of damages, in its name or in the name of the policyholder, against a third party who is liable for costs relating to an insured event that have been paid by the insurer. Estimated salvage and subrogation is generally deducted from the liability for unpaid claims.

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Financial Guarantee Insurance Contracts Financial Guarantee Insurance Contracts Earned Premiums by Geographic Location (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 47	$ 54	$ 66
Premiums Receivable, Gross	329	387
Liability for Claims and Claims Adjustment Expense	1,570	1,759	(482)	$ (107)
Subrogation recoverable	2,092	2,156
Financial Guarantee
Liability for Claims and Claims Adjustment Expense	1,538
Subrogation recoverable	(2,092)
Property and Casualty, Commercial Insurance
Liability for Claims and Claims Adjustment Expense	32
Subrogation recoverable	0
Public Finance [Member]
Premiums Receivable, Gross	159	185
Structured Finance [Member]
Premiums Receivable, Gross	45	59
International Finance [Member]
Premiums Receivable, Gross	125	144
Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	157	168
Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	2	17
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	16	22
Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	12	16
Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	10	14
Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	7	7
Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	93	108
Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	28	31
Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	5	5
Surveillance Category One [Member]
Premiums Receivable, Gross	277	302
Surveillance Category One [Member] \| Public Finance [Member]
Premiums Receivable, Gross	151	157
Surveillance Category One [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	19	27
Surveillance Category One [Member] \| International Finance [Member]
Premiums Receivable, Gross	107	118
Surveillance Category One [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	149	155
Surveillance Category One [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	2	2
Surveillance Category One [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	3
Surveillance Category One [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	3
Surveillance Category One [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	10	14
Surveillance Category One [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	7	7
Surveillance Category One [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	74	82
Surveillance Category One [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	28	31
Surveillance Category One [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	5	5
IA [Member]
Premiums Receivable, Gross	12	40
IA [Member] \| Public Finance [Member]
Premiums Receivable, Gross	3	27
IA [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	0
IA [Member] \| International Finance [Member]
Premiums Receivable, Gross	8	13
IA [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	3	13
IA [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	15
IA [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	0
IA [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	8	13
IA [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member]
Premiums Receivable, Gross	6	3
II [Member] \| Public Finance [Member]
Premiums Receivable, Gross	5	0
II [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	3
II [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	5	0
II [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	1
II [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	2
II [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
III [Member]
Premiums Receivable, Gross	22	27
III [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	12	14
III [Member] \| International Finance [Member]
Premiums Receivable, Gross	11	13
III [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	2	3
III [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	9	11
III [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	11	13
III [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member]
Premiums Receivable, Gross	12	15
IV [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	12	15
IV [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	12	15
IV [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
Reportable Geographical Components [Member] \| UNITED STATES
Premiums Earned, Net, Financial Guarantee Insurance Contracts	27	32	55
Reportable Geographical Components [Member] \| UNITED KINGDOM
Premiums Earned, Net, Financial Guarantee Insurance Contracts	14	24	17
Reportable Geographical Components [Member] \| Other International [Member]
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 6	$ (2)	$ (6)