DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE IMPACT ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	$ 19	$ (17)	$ (129)	$ 7
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Pretax gain (loss) recognized in OCI	36	(68)	(225)	(250)
Pretax (loss) gain reclassified from AOCI into earnings	(4)	(8)	(43)	(16)
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	14	(7)	(73)	(25)
Pretax (loss) gain reclassified from AOCI into earnings	(3)	(1)	(7)	(2)
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	(5)	(33)	0
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
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
Pretax (loss) gain reclassified from AOCI into earnings			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	24	(62)	(166)	(222)
Pretax (loss) gain reclassified from AOCI into earnings	(5)	(2)	(6)	(3)
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	(2)	1	14	(3)
Pretax (loss) gain reclassified from AOCI into earnings			2	(1)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Pretax gain (loss) on derivatives recognized in earnings	17	(5)	(37)	8
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	15	(12)	(97)	7
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	(39)	(8)	25	9
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	41	18	41	(7)
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	0	(3)	(6)	(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 gain (loss) recognized in OCI	0	0	0	(1)
Pretax (loss) gain reclassified from AOCI into earnings	0	(1)	0	(3)
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	41	18	41	(7)
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 gain (loss) recognized in OCI	0	0	0	0
Pretax (loss) gain reclassified from AOCI into earnings	0	(1)	0	(1)
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	$ 0	$ (3)	$ (6)	$ (1)