DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE IMPACT ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	$ 5	$ 11	$ (148)	$ 24
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	(18)	(108)	(261)	(182)
Pretax (loss) gain reclassified from AOCI into earnings	0	(8)	(39)	(8)
Designated as Hedging Instrument [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	5	(15)	(87)	(18)
Pretax (loss) gain reclassified from AOCI into earnings	(2)	0	(4)	(1)
Designated as Hedging Instrument [Member] | Other Income (Expense), Net [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax (loss) gain reclassified from AOCI into earnings	4	2	(37)	5
Designated as Hedging Instrument [Member] | Other Income (Expense), Net [Member] | Cash Flow Hedging [Member] | Foreign Exchange Instruments [Member]
Derivative [Line Items]
Pretax (loss) gain reclassified from AOCI into earnings	(1)	0	1	0
Designated as Hedging Instrument [Member] | Gain On Sale Of Assets [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	0	0	0	0
Pretax (loss) gain reclassified from AOCI into earnings	0	(10)	0	(10)
Designated as Hedging Instrument [Member] | Equity Earnings [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	(18)	(92)	(190)	(160)
Pretax (loss) gain reclassified from AOCI into earnings	(1)	0	(1)	(1)
Designated as Hedging Instrument [Member] | Revenues: Energy-Related Businesses [Member] | Cash Flow Hedging [Member] | Foreign Exchange Instruments [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	(5)	(1)	16	(4)
Pretax (loss) gain reclassified from AOCI into earnings	0	0	2	(1)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	21	(1)	(54)	13
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 gain (loss) on derivatives recognized in earnings	9	(27)	0	(25)
Not Designated as Hedging Instrument [Member] | Other Income (Expense), Net [Member] | Foreign Exchange Instruments [Member]
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	2	9	(112)	19
Not Designated as Hedging Instrument [Member] | Revenues: Energy-Related Businesses [Member] | Commodity Contracts not subject to rate recovery [Member]
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	13	17	64	17
Not Designated as Hedging Instrument [Member] | Cost of Natural Gas [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	(3)	0	(6)	2
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 gain (loss) recognized in OCI	0	(1)	0	(1)
Pretax (loss) gain reclassified from AOCI into earnings	0	(1)	0	(2)
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 gain (loss) on derivatives recognized in earnings	9	(27)	0	(25)
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 gain (loss) on derivatives recognized in earnings	$ (3)	$ 0	$ (6)	$ 2