| Document and Entity Information | Oct. 21, 2019 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 21, 2019 |
| Entity Registrant Name | Buckeye Partners, L.P. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-09356 |
| 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 |
| Entity Central Index Key | 0000805022 |
| Title of 12(b) Security | Limited partner units representing limited partnership interests |
| Trading Symbol | BPL |
| Security Exchange Name | NYSE |
