| Document and Entity Information | Aug. 05, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | ONCOR ELECTRIC DELIVERY CO LLC |
| Entity Incorporation State Country Code | DE |
| Amendment Flag | false |
| Entity Central Index Key | 0001193311 |
| Document Type | 8-K |
| Document Period End Date | Aug. 5, 2021 |
| Entity File Number | 333-100240 |
| Entity Tax Identification Number | 75-2967830 |
| Entity Address, Address Line One | 1616 Woodall Rodgers Fwy. |
| Entity Address, City or Town | Dallas |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75202 |
| City Area Code | (214) |
| Local Phone Number | 486-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
