Basis of Financial Statements - Future Policy Benefits (Details) - Life and Annuity Insurance Product Line	Sep. 30, 2020
Maximum
Ceded Credit Risk [Line Items]
Investment yield assumptions	5.70%
Minimum
Ceded Credit Risk [Line Items]
Investment yield assumptions	2.50%

Estimated average rate of return on investments which is included in the calculation of the amount of the specified guaranteed benefit obligation as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 55
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121639652&loc=d3e7104-158389

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121643868&loc=d3e14937-158439

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 80
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121641442&loc=d3e19393-158473

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121643868&loc=d3e14944-158439

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121638524&loc=d3e11318-158416

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121643868&loc=d3e14931-158439

Name:	us-gaap_LongDurationContractsAssumptionsByProductAndGuaranteeEstimatedAverageInvestmentYield
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant