| Document and Entity Information | Nov. 01, 2019 |
| Document And Entity Information [Line Items] | |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0000805022 |
| Document Type | 8-K |
| Document Period End Date | Nov. 1, 2019 |
| Entity Registrant Name | Buckeye Partners, L.P. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-9356 |
| Entity Tax Identification Number | 23-2432497 |
| Entity Address, Address Line One | One Greenway Plaza |
| Entity Address, Address Line Two | Suite 600 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77046 |
| City Area Code | 832 |
| Local Phone Number | 615-8600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Security 12b Title | Limited partner units representing limited partnership interests |
| Trading Symbol | BPL |
| Security Exchange Name | NYSE |
