Financial Guarantee Insurance Contracts - Summarized Future Gross Undiscounted Premiums Expected to be Collected, and Future Expected Premiums Earned, Net of Reinsurance (Details) $ in Millions	Jun. 30, 2021 USD ($)
Future premiums expected to be collected, September 30, 2021	$ 10
Future premiums expected to be collected, December 31, 2021	8
Future premiums expected to be collected, December 31, 2022	34
Future premiums expected to be collected, December 31, 2023	32
Future premiums expected to be collected, December 31, 2024	31
Future premiums expected to be collected, December 31, 2025	30
Future premiums expected to be collected, December 31, 2030	126
Future premiums expected to be collected, December 31, 2035	88
Future premiums expected to be collected, December 31, 2040	42
Future premiums expected to be collected, December 31, 2045	19
Future premiums expected to be collected, December 31, 2050	7
Future premiums expected to be collected, December 31, 2055	1
Future premiums expected to be collected, Total	425
Future expected premiums to be earned, net of reinsurance, September 30, 2021	8
Future expected premiums to be earned, net of reinsurance, December 31, 2021	8
Future expected premiums to be earned, net of reinsurance, December 31, 2022	30
Future expected premiums to be earned, net of reinsurance, December 31, 2023	28
Future expected premiums to be earned, net of reinsurance, December 31, 2024	27
Future expected premiums to be earned, net of reinsurance, December 31, 2025	25
Future expected premiums to be earned, net of reinsurance, December 31, 2030	105
Future expected premiums to be earned, net of reinsurance, December 31, 2035	66
Future expected premiums to be earned, net of reinsurance, December 31, 2040	28
Future expected premiums to be earned, net of reinsurance, December 31, 2045	11
Future expected premiums to be earned, net of reinsurance, December 31, 2050	4
Future expected premiums to be earned, net of reinsurance, December 31, 2055	0
Future expected premiums to be earned, net of reinsurance, Total	$ 341

Amount of unearned premium revenue under contracts issued by an insurance entity that provide protection to the holder of a financial obligation from a financial loss in the event of a default.

No definition available.

+ Details

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- Definition

Amount of premium revenue under financial guarantee insurance contract to be recognized in fourth fiscal quarter following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6933581&loc=SL5749298-161291

+ Details

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- Definition

Amount of premium revenue under financial guarantee insurance contract to be recognized in third fiscal quarter following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of premium revenue under financial guarantee insurance contract to be recognized in eleventh through fifteenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References