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Financial Guarantees in Force - Summary of International Finance Guaranteed Portfolio (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 46,927,000	$ 62,716,000
International Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	13,538,000	16,812,000
International Finance [Member] | United Kingdom [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	10,965,000	13,554,000
International Finance [Member] | Australia [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	384,000	608,000
International Finance [Member] | Italy [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	811,000	877,000
International Finance [Member] | Austria [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	712,000	770,000
International Finance [Member] | FRANCE
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	312,000	329,000
International Finance [Member] | Internationally Diversified [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	213,000	368,000
International Finance [Member] | Other International [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 141,000	$ 306,000

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of participating insurance in force.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 50
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6483535&loc=d3e16392-158451

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