COMMITMENTS AND CONTINGENCIES - LESSEE CASH FLOW INFORMATION (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	$ 39,000,000
Cash paid for finance leases	43,000,000
Cash paid for finance leases	5,000,000
Increase in operating lease obligations for right-of-use assets	552,000,000
Increase in finance lease obligations for investment in PP&E	7,000,000	$ 5,000,000
Southern California Gas Company [Member]
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	7,000,000
Cash paid for finance leases	0
Cash paid for finance leases	1,000,000	0
Increase in operating lease obligations for right-of-use assets	117,000,000
Increase in finance lease obligations for investment in PP&E	3,000,000	5,000,000
San Diego Gas and Electric Company [Member]
Lessee, Lease, Description [Line Items]
Cash paid for operating leases	8,000,000
Cash paid for finance leases	43,000,000
Cash paid for finance leases	4,000,000
Increase in operating lease obligations for right-of-use assets	142,000,000
Increase in finance lease obligations for investment in PP&E	$ 4,000,000	$ 0