DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE IMPACT ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings			$ 12	$ 44
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	$ (68)	$ 31	(250)	173
Pretax (loss) gain reclassified from AOCI into earnings	(8)	8	(16)	5
Designated as Hedging Instrument [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	(7)	16	(25)	57
Pretax (loss) gain reclassified from AOCI into earnings	(1)	0	(2)	1
Designated as Hedging Instrument [Member] | Other (Expense) Income, Net [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax (loss) gain reclassified from AOCI into earnings	(5)	11	0	11
Designated as Hedging Instrument [Member] | Gain (Loss) On Sale Of Assets [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI			0	0
Pretax (loss) gain reclassified from AOCI into earnings			(10)	0
Designated as Hedging Instrument [Member] | Equity Earnings [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	(62)	20	(222)	123
Pretax (loss) gain reclassified from AOCI into earnings	(2)	(3)	(3)	(8)
Designated as Hedging Instrument [Member] | Revenues: Energy-Related Businesses [Member] | Cash Flow Hedging [Member] | Foreign Exchange Instruments [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	1	(5)	(3)	(7)
Pretax (loss) gain reclassified from AOCI into earnings	0	0	(1)	1
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	(5)	97	8	104
Not Designated as Hedging Instrument [Member] | Other (Expense) Income, Net [Member] | Foreign Exchange Instruments [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	(12)	28	7	35
Not Designated as Hedging Instrument [Member] | Revenues: Energy-Related Businesses [Member] | Commodity Contracts not subject to rate recovery [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	(8)	9	9	0
Not Designated as Hedging Instrument [Member] | Cost of Electric Fuel and Purchased Power [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	18	62	(7)	70
Not Designated as Hedging Instrument [Member] | Cost of Natural Gas [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	(3)	(2)	(1)	(1)
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	0	0	(1)	1
Pretax (loss) gain reclassified from AOCI into earnings	(1)	(2)	(3)	(6)
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Cost of Electric Fuel and Purchased Power [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	18	62	(7)	70
Southern California Gas Company [Member] | Designated as Hedging Instrument [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Pretax (loss) gain recognized in OCI	0	0	0	0
Pretax (loss) gain reclassified from AOCI into earnings	(1)	0	(1)	0
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Cost of Natural Gas [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Pretax (loss) gain on derivatives recognized in earnings	$ (3)	$ (2)	$ (1)	$ (1)