| TaxonomyVersion | 2018 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2017-07 | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedLabels | true | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedDocumentation | true | http://fasb.org/srt/role/changeNote/changeNote |
| PreviousDocumentation | Indicates (true/false) whether appreciation (depreciation) on open futures contract of underlying constitutes more than five percent of net assets. | http://fasb.org/srt/role/changeNote/changeNote |
| Publisher | FASB | http://fasb.org/us-gaap/role/ref/legacyRef |
| Name | Accounting Standards Codification | http://fasb.org/us-gaap/role/ref/legacyRef |
| Topic | 946 | http://fasb.org/us-gaap/role/ref/legacyRef |
| SubTopic | 210 | http://fasb.org/us-gaap/role/ref/legacyRef |
| Section | 50 | http://fasb.org/us-gaap/role/ref/legacyRef |
| Paragraph | 6 | http://fasb.org/us-gaap/role/ref/legacyRef |
| Subparagraph | (e) | http://fasb.org/us-gaap/role/ref/legacyRef |
| URI | http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841 | http://fasb.org/us-gaap/role/ref/legacyRef |