COMMITMENTS AND CONTINGENCIES - LEASE INCOME STATEMENT INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 92	$ 96
Amortization of ROU assets	35	24
Interest on lease liabilities	188	173
Total finance lease costs	223	197
Short-term lease costs	7	6
Variable lease costs	477	482
Total lease costs	799	781
Depreciation and Amortization Expense [Member]
Lessee, Lease, Description [Line Items]
Amortization of ROU assets	18	15
San Diego Gas and Electric Company [Member]
Lessee, Lease, Description [Line Items]
Operating lease costs	31	33
Amortization of ROU assets	23	18
Interest on lease liabilities	186	173
Total finance lease costs	209	191
Short-term lease costs	3	2
Variable lease costs	467	471
Total lease costs	710	697
San Diego Gas and Electric Company [Member] | Depreciation and Amortization Expense [Member]
Lessee, Lease, Description [Line Items]
Amortization of ROU assets	18	15
Southern California Gas Company [Member]
Lessee, Lease, Description [Line Items]
Operating lease costs	24	27
Amortization of ROU assets	12	6
Interest on lease liabilities	2	0
Total finance lease costs	14	6
Short-term lease costs	0	0
Variable lease costs	10	10
Total lease costs	$ 48	$ 43