ACQUISTION AND DIVESTITURE ACTIVITY - ASSETS ACQUIRED AND LIABILITIES ASSUMED (Details) - USD ($) $ in Millions					3 Months Ended			12 Months Ended
	Dec. 18, 2018	Mar. 09, 2018	Dec. 14, 2016	Sep. 26, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Fair value of equity interest in IEnova Pipelines immediately prior to acquisition								$ 0	$ 28	$ 1,144
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Goodwill					$ 2,373	$ 2,397	$ 2,364	2,373	2,397	2,364
Acquisition of business – measurement period adjustment									$ (13)
Compania Transmisora del Norte Grande S.A. [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents	$ 18
Other current assets	5
Other intangible assets	46
Property, plant and equipment	162
Total assets acquired	231
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Other current liabilities	1
Deferred income taxes	42
Total liabilities assumed	43
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	188
Goodwill	38
Consideration transferred	$ 226
Oncor Holdings Electric Delivery Company LLC [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Accounts receivable		$ 1
Due from unconsolidated affiliates		46
Investment in Oncor Holdings		9,227
Deferred income taxes		287
Other noncurrent assets		109
Total assets acquired		9,670
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Other current liabilities		23
Pension and other postretirement benefit plan obligations		21
Deferred credits and other		58
Total liabilities assumed		102
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		9,568
Consideration transferred		$ 9,568
Oncor Holdings Electric Delivery Company LLC [Member] | Scenario, Adjustment [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Investment in Oncor Holdings					64			64
Deferred income taxes					66			66
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Deferred credits and other					2			2
Consideration transferred					2
Sempra Mexico [Member] | IEnova Pipelines [Member]
Business Acquisition [Line Items]
Cash consideration (fair value of total consideration)				$ 1,144
Fair value of equity interest in IEnova Pipelines immediately prior to acquisition				1,144
Total fair value of business combination				2,288
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents				66
Restricted cash				0
Accounts receivable				39
Other current assets				6
Other intangible assets				0
Deferred income taxes				0
Regulatory assets				33
Property, plant and equipment				1,248
Other noncurrent assets				1
Total assets acquired				1,393
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Short-term debt				0
Accounts payable				11
Due to unconsolidated affiliates				3
Current portion of long-term debt				49
Fixed-price contracts and other derivatives, current				6
Other current liabilities				20
Long-term debt				315
Asset retirement obligations				5
Deferred income taxes				127
Fixed-price contracts and other derivatives, noncurrent				19
Other noncurrent liabilities				11
Total liabilities assumed				566
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net				827
Goodwill				$ 1,461
Sempra Mexico [Member] | IEnova Pipelines [Member] | Scenario, Adjustment [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Regulatory assets							33			33
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Deferred income taxes							119			$ 119
Acquisition of business – measurement period adjustment							$ 86
Sempra Mexico [Member] | Ventika [Member]
Business Acquisition [Line Items]
Cash consideration (fair value of total consideration)			$ 310
Fair value of equity interest in IEnova Pipelines immediately prior to acquisition			0
Total fair value of business combination			310
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents			0
Restricted cash			68
Accounts receivable			14
Other current assets			1
Other intangible assets			154
Deferred income taxes			36
Regulatory assets			0
Property, plant and equipment			673
Other noncurrent assets			3
Total assets acquired			949
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Short-term debt			125
Accounts payable			1
Due to unconsolidated affiliates			0
Current portion of long-term debt			7
Fixed-price contracts and other derivatives, current			4
Other current liabilities			8
Long-term debt			478
Asset retirement obligations			2
Deferred income taxes			120
Fixed-price contracts and other derivatives, noncurrent			10
Other noncurrent liabilities			0
Total liabilities assumed			755
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			194
Goodwill			$ 116
Sempra Mexico [Member] | Ventika [Member] | Scenario, Adjustment [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Deferred income taxes					$ 13			$ 13
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Acquisition of business – measurement period adjustment						$ (13)