| Name | HedgeFundsMember |
|---|---|
| Namespace | http://fasb.org/us-gaap/2020-01-31 |
| Prefix | us-gaap |
| Data type | nonnum:domainItemType |
| Period type | duration |
| Substitution Group | xbrli:item |
| Balance | None |
| Nillable | True |
| Abstract | True |
| Text | Lang | Role | Container role |
|---|---|---|---|
| Hedge Funds [Member] | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Investments in registered hedge funds. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Name | Value | Role |
|---|---|---|
| SourceName | Retirement Benefits:Taxonomy Technical Improvement | http://fasb.org/srt/role/changeNote/changeNote |
| TaxonomyVersion | 2018 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2017-08 | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedReferences | true | http://fasb.org/srt/role/changeNote/changeNote |
| Publisher | FASB | http://www.xbrl.org/2009/role/commonPracticeRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2009/role/commonPracticeRef |
| Topic | 715 | http://www.xbrl.org/2009/role/commonPracticeRef |
| SubTopic | 20 | http://www.xbrl.org/2009/role/commonPracticeRef |
| Section | 50 | http://www.xbrl.org/2009/role/commonPracticeRef |
| Paragraph | 1 | http://www.xbrl.org/2009/role/commonPracticeRef |
| Subparagraph | (d)(ii) | http://www.xbrl.org/2009/role/commonPracticeRef |
| URI | http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 | http://www.xbrl.org/2009/role/commonPracticeRef |
| Name | Relation Type | Role | |
|---|---|---|---|
us-gaap:HedgeFundsEquityMember | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists | |
us-gaap:HedgeFundsEventDrivenMember | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists | |
us-gaap:HedgeFundsGlobalOpportunityMember | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists | |
us-gaap:HedgeFundsMultistrategyMember | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists | |
us-gaap:HedgeFundsEquityLongShortMember | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists |
| Name | Relation Type | Role | |
|---|---|---|---|
us-gaap:TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists | |
us-gaap:TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain | parent-child | http://fasb.org/us-gaap/role/disclosure/FairValueMeasuresAndDisclosuresTmp01 | |
us-gaap:TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain | domain-member | http://fasb.org/us-gaap/role/disclosure/FairValueMeasuresAndDisclosuresTmp01FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable |