| Cover | Feb. 25, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 25, 2021 |
| Entity Registrant Name | SOUTHERN CALIFORNIA GAS COMPANY |
| Entity Incorporation, State or Country Code | CA |
| Entity File Number | 1-01402 |
| Entity Tax Identification Number | 95-1240705 |
| Entity Address, Address Line One | 555 West Fifth Street |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90013 |
| City Area Code | (213) |
| Local Phone Number | 244-1200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0000092108 |
