GENERAL INFORMATION AND OTHER FINANCIAL DATA - CAPITALIZED FINANCING COSTS (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Capitalized Financing Costs Disclosure [Line Items] | ||
| Total capitalized financing costs | $ 51 | $ 82 |
| San Diego Gas and Electric Company [Member] | ||
| Capitalized Financing Costs Disclosure [Line Items] | ||
| Total capitalized financing costs | 24 | 20 |
| Southern California Gas Company [Member] | ||
| Capitalized Financing Costs Disclosure [Line Items] | ||
| Total capitalized financing costs | $ 13 | $ 15 |