COMMITMENTS AND CONTINGENCIES - LEASES CASH FLOW INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	$ 101
Cash paid for finance leases	173
Cash paid for finance leases	24
Increase in operating lease obligations for right-of-use assets	585
Increase in finance lease obligations for investment in property, plant and equipment	38	$ 556	$ 503
Southern California Gas Company [Member]
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	27
Cash paid for finance leases	0
Cash paid for finance leases	6
Increase in operating lease obligations for right-of-use assets	118
Increase in finance lease obligations for investment in property, plant and equipment	22	6	3
San Diego Gas and Electric Company [Member]
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	33
Cash paid for finance leases	173
Cash paid for finance leases	18
Increase in operating lease obligations for right-of-use assets	158
Increase in finance lease obligations for investment in property, plant and equipment	$ 16	$ 550	$ 500