| Cover Page | Aug. 09, 2021 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 9, 2021 |
| Entity Registrant Name | SAN DIEGO GAS & ELECTRIC CO |
| Entity File Number | 1-03779 |
| Entity Central Index Key | 0000086521 |
| Entity Incorporation, State or Country Code | CA |
| Entity Tax Identification Number | 95-1184800 |
| Entity Address, Address Line One | 8326 Century Park Court |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92123 |
| City Area Code | 619 |
| Local Phone Number | 696-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Sempra Energy Common Stock, without par value [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Sempra Energy Common Stock, without par value |
| Trading Symbol | SRE |
| Security Exchange Name | NYSE |
| Sempra Energy 5.75% Junior Subordinated Notes Due 2029, $25 par value [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Sempra Energy 5.75% Junior Subordinated Notes Due 2079, $25 par value |
| Trading Symbol | SREA |
| Security Exchange Name | NYSE |
| SEMPRA ENERGY [Member] | |
| Document Information [Line Items] | |
| Entity Registrant Name | SEMPRA ENERGY |
| Entity File Number | 1-14201 |
| Entity Incorporation, State or Country Code | CA |
| Entity Tax Identification Number | 33-0732627 |
| Entity Address, Address Line One | 488 8th Avenue |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92101 |
| City Area Code | 619 |
| Local Phone Number | 696-2000 |
| Entity Emerging Growth Company | false |
