Commitments, Guarantees and Contingent Liabilities - Guaranty funds and Guarantees (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Guaranty Funds
Loss Contingencies
Liability for insurance assessments	$ 12,000,000	$ 13,000,000
Insurance assessments, premium tax offsets	14,000,000	$ 15,000,000
Minimum
Loss Contingencies
Reasonably possible additional losses	0
Maximum
Loss Contingencies
Reasonably possible additional losses	$ 85,000,000

Estimate of the reasonably possible pretax loss exposure in excess of the amount accrued for the entity's lawsuits, regulatory inquiries and other legal proceedings.

No definition available.

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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

The amount of insurance-related assessment liability that is expected to be recovered through a premium tax offset based on current laws applied to in-force policies.

+ References

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- Definition

The liability as of the balance sheet date representing required funding mandated by statute or regulatory authority that is related directly or indirectly to underwriting activities, including pools for self-insurance and excluding premium taxes and income taxes. The funds derived from the assessments generally enable a government guarantor to pay insurance claims in the event that the underwriting insurer is insolvent or otherwise unable to meet its payment obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 405
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6392405&loc=d3e24119-109301

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 405
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=99384745&loc=d3e23169-109297

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