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Schedule IV - (Reinsurance) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Direct Amount	$ 8	$ 1	$ 3
Ceded to Others	2	1	0
Assumed From Other Companies	0	0	0
Net Amount	$ 6	$ 0	$ 3
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%

X

- Definition

Direct amount premiums written.

+ References

No definition available.

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X

- Definition

Premiums written financial guarantee insurance contracts percentage of amount assumed to net.

+ References

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X

- References

No definition available.

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X

- Definition

Amount of written premiums assumed from other entities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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X

- Definition

Amount of written premiums ceded to other entities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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X

- Definition

Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums written.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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