| elementCreationTaxonomyVersion | 2018 | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Source | Taxonomy Implementation Guide | http://fasb.org/us-gaap/role/tin/resource |
| SourceName | Retirement Benefits-Phase 2 | http://fasb.org/us-gaap/role/tin/resource |
| pdfURI | https://www.fasb.org/retirementbenefitsphase2 | http://fasb.org/us-gaap/role/tin/resource |
| Publisher | FASB | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2003/role/disclosureRef |
| Topic | 820 | http://www.xbrl.org/2003/role/disclosureRef |
| SubTopic | 10 | http://www.xbrl.org/2003/role/disclosureRef |
| Section | 35 | http://www.xbrl.org/2003/role/disclosureRef |
| Paragraph | 54B | http://www.xbrl.org/2003/role/disclosureRef |
| URI | https://asc.fasb.org/extlink&oid=126972413&loc=SL7495116-110257 | http://www.xbrl.org/2003/role/disclosureRef |
| Publisher | FASB | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2003/role/disclosureRef |
| Topic | 820 | http://www.xbrl.org/2003/role/disclosureRef |
| SubTopic | 10 | http://www.xbrl.org/2003/role/disclosureRef |
| Section | 50 | http://www.xbrl.org/2003/role/disclosureRef |
| Paragraph | 6A | http://www.xbrl.org/2003/role/disclosureRef |
| URI | https://asc.fasb.org/extlink&oid=126976982&loc=SL6742756-110258 | http://www.xbrl.org/2003/role/disclosureRef |
| Publisher | FASB | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2003/role/disclosureRef |
| Topic | 715 | http://www.xbrl.org/2003/role/disclosureRef |
| SubTopic | 20 | http://www.xbrl.org/2003/role/disclosureRef |
| Section | 50 | http://www.xbrl.org/2003/role/disclosureRef |
| Paragraph | 1 | http://www.xbrl.org/2003/role/disclosureRef |
| Subparagraph | (d)(iv)(01) | http://www.xbrl.org/2003/role/disclosureRef |
| URI | https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 | http://www.xbrl.org/2003/role/disclosureRef |