INVESTMENTS IN UNCONSOLIDATED ENTITIES - NARRATIVE (Details) $ in Millions	1 Months Ended	12 Months Ended
	Feb. 28, 2017 USD ($)	Dec. 31, 2017 USD ($) MT Bcf	Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)		Nov. 15, 2017	Nov. 14, 2017	Sep. 26, 2016	Sep. 25, 2016	May 31, 2016	May 09, 2016	Mar. 31, 2016 USD ($)	Mar. 29, 2016	Jun. 30, 2015 USD ($)	Nov. 30, 2014 USD ($)	Oct. 01, 2014 USD ($)
Schedule of Equity Method Investments [Line Items]
Undistributed earnings of equity method investments		$ 89	$ 44
Equity method investment		2,517	2,080
Debt instrument converted		19	0	[1]	$ 0	[1]
Interest costs capitalized		256	236		201
Fair value at origin guarantee obligation associated with cash flow requirements																	$ 82
Current guarantor obligations		26
R B S Sempra Commodities [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment		$ 67
Cameron LNG [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage in equity method investee		50.20%
Threshold for canceling of hedge, Percent of unamortized principal		50.00%
Indirect economic and beneficial and ownership interest prior to financial completion		37.65%
Indirect economic and beneficial and ownership interest after financial completion		10.00%
Cameron LNG [Member] | Other Long Term Debt, Due July 2030 [Member]
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Percentage		50.20%
Debt instrument, maximum borrowing amount		$ 3,900
Sempra Energy and Other [Member] | R B S Sempra Commodities [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment		67	67
Sempra Mexico [Member] | IEnova Pipelines [Member]
Schedule of Equity Method Investments [Line Items]
Acquired percentage interest									50.00%
Ownership percentage in equity method investee										50.00%
Sempra Mexico [Member] | IMG [Member]
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		$ 72	100
Ownership percentage in equity method investee		40.00%
Transportation service contract term		25 years
Sempra Mexico [Member] | TransCanada [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage in equity method investee		60.00%
Sempra Mexico [Member] | DEN [Member] | IEnova Pipelines [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage in equity method investee									50.00%
Sempra Renewables [Member]
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments			18		21
Ownership percentage of operating partner		50.00%
Sempra LNG & Midstream [Member] | Rockies Express [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment													$ 484
Payments to acquire equity method investments					113
Ownership percentage in equity method investee											25.00%	25.00%	25.00%	25.00%
Sempra LNG & Midstream [Member] | Cameron LNG [Member]
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		$ 1			10
Proved developed reserves | Bcf		1.5
Project capacity | MT		13.9
Proved undeveloped reserve | MT		12
Proved undeveloped reserve per day | Bcf		1.7
Interest costs capitalized		$ 47	$ 47		$ 49
Debt amount		$ 7,400
Percentage of debt hedged by interest rate derivatives		50.00%
Notional amount of derivatives															$ 1,500	$ 3,700
Sempra LNG & Midstream [Member] | LIBOR [Member] | Cameron LNG [Member]
Schedule of Equity Method Investments [Line Items]
Weighted average rate prior to project completion		1.59%
Weighted average rate after project completion		1.78%
Fixed percentage interest rate															3.32%	3.19%
Corporate Joint Venture [Member] | Sempra South American Utilities [Member] | Eletrans [Member]
Schedule of Equity Method Investments [Line Items]
Debt instrument converted	$ 19
Payments to acquire equity method investments		$ 1
Corporate Joint Venture [Member] | Sempra Mexico [Member] | IEnova [Member] | IMG [Member]
Schedule of Equity Method Investments [Line Items]
Debt instrument, maximum borrowing amount		$ 288
Other Project Partners [Member] | Cameron LNG [Member] | Other Long Term Debt, Due July 2030 [Member]
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Percentage		49.80%
Ductos Energéticos del Norte [Member] | Sempra Mexico [Member] | IEnova [Member]
Schedule of Equity Method Investments [Line Items]
Acquired percentage interest							50.00%
Ownership percentage in equity method investee								50.00%

[1] As adjusted for the retrospective adoption of ASU 2016-15 and ASU 2016-18, which we discuss in Note 2.