DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE IMPACT ON INCOME (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings			$ 142,000,000	$ (41,000,000)	[1]
Fair Value Hedging [Member] | Interest Expense [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedge ineffectiveness		$ 0		0
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings		(1,000,000)		1,000,000
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Interest Expense [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings		1,000,000		3,000,000
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Other Income, Net [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings		(2,000,000)		(2,000,000)
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	$ (50,000,000)	(89,000,000)	(54,000,000)	(254,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	(3,000,000)	(10,000,000)	(15,000,000)	(11,000,000)
Loss on cash flow hedge ineffectiveness	2,000,000	0	(2,000,000)	0
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Expense [Member] | Interest rate and foreign exchange instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	(8,000,000)	1,000,000	8,000,000	(10,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	1,000,000	(3,000,000)	4,000,000	(7,000,000)
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Equity Earnings, Before Income Tax [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	(32,000,000)	(70,000,000)	(37,000,000)	(207,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	(2,000,000)	(2,000,000)	(4,000,000)	(5,000,000)
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Equity Earnings, Net of Income Tax [Member] | Interest rate and foreign exchange instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	(9,000,000)	(15,000,000)	(18,000,000)	(33,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	(3,000,000)	(5,000,000)	(5,000,000)	(6,000,000)
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Revenues: Energy- Related Businesses [Member] | Foreign exchange instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	(1,000,000)	0	(10,000,000)	0
Pretax gain (loss) reclassified from AOCI into earnings	1,000,000	0	(1,000,000)	0
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Revenues: Energy- Related Businesses [Member] | Commodity contracts not subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	0	(5,000,000)	3,000,000	(4,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	0	0	(9,000,000)	7,000,000
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	54,000,000	1,000,000	103,000,000	(12,000,000)
Not Designated as Hedging Instrument [Member] | Other Income, Net [Member] | Foreign exchange instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	32,000,000	(15,000,000)	97,000,000	(12,000,000)
Not Designated as Hedging Instrument [Member] | Equity Earnings, Net of Income Tax [Member] | Foreign exchange instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	0	0	0	2,000,000
Not Designated as Hedging Instrument [Member] | Revenues: Energy- Related Businesses [Member] | Commodity contracts not subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	16,000,000	(24,000,000)	30,000,000	(29,000,000)
Not Designated as Hedging Instrument [Member] | Operation and Maintenance [Member] | Commodity contracts not subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	0	1,000,000	(1,000,000)	1,000,000
Not Designated as Hedging Instrument [Member] | Cost of Electric Fuel and Purchased Power [Member] | Commodity contracts subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	6,000,000	40,000,000	(23,000,000)	28,000,000
Not Designated as Hedging Instrument [Member] | Cost of Natural Gas [Member] | Commodity contracts subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	0	(1,000,000)	0	(2,000,000)
San Diego Gas and Electric Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings			1,000,000	1,000,000	[1]
San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Expense [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss on cash flow hedge ineffectiveness	0	0	0	0
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Expense [Member] | Interest rate instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax (loss) gain recognized in OCI	(2,000,000)	(2,000,000)	(2,000,000)	(7,000,000)
Pretax gain (loss) reclassified from AOCI into earnings	(3,000,000)	(3,000,000)	(6,000,000)	(6,000,000)
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 Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	6,000,000	40,000,000	(23,000,000)	28,000,000
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	0	(1,000,000)	(1,000,000)	(2,000,000)
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Operation and Maintenance [Member] | Commodity contracts not subject to rate recovery [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	0	0	(1,000,000)	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 Instruments, Gain (Loss) [Line Items]
Pretax gain on derivatives recognized in earnings	$ 0	$ (1,000,000)	$ 0	$ (2,000,000)

[1] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.