DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE IMPACT ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 27	$ 35
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	14	38
Not Designated as Hedging Instrument [Member] | Other Income [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	10	44
Not Designated as Hedging Instrument [Member] | Sales [Member] | Commodity Contracts not subject to rate recovery [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(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]
Derivative, Gain (Loss) on Derivative, Net	2	2
Not Designated as Hedging Instrument [Member] | Cost of Natural Gas [Member] | Commodity Contracts Subject To Rate Recovery [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	1
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(74)	117
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	16
Designated as Hedging Instrument [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(3)	54
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)	2
Designated as Hedging Instrument [Member] | Other Income [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	3	18
Designated as Hedging Instrument [Member] | Equity Earnings (Losses) [Member] | Cash Flow Hedging [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(68)	70
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)	(4)
Designated as Hedging Instrument [Member] | Sales [Member] | Cash Flow Hedging [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(3)	(7)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)	0
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]
Derivative, Gain (Loss) on Derivative, Net	2	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]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	0	1
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)	(3)
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]
Derivative, Gain (Loss) on Derivative, Net	$ 2	$ 1