GENERAL INFORMATION AND OTHER FINANCIAL DATA - SHAREHOLDER'S EQUITY AND NONCONTROLLING INTEREST (Details) $ / shares in Units, $ in Millions					1 Months Ended	3 Months Ended			9 Months Ended
	Nov. 07, 2018 shares	Jul. 13, 2018 USD ($) shares $ / shares Rate	Mar. 08, 2018 USD ($) shares	Jan. 09, 2018 USD ($) $ / shares shares	Jan. 31, 2018 USD ($)	Sep. 30, 2018 $ / shares	Jun. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($) shares	Sep. 30, 2018 USD ($) $ / shares	Sep. 30, 2017 USD ($)	[1]
Proceeds from issuance | $									$ 2,259	$ 0
Proceeds from issuance | $									$ 2,261	$ 37
Common Stock [Member]
Shares issued | shares		11,212,500	8,556,630	26,869,158			7,651,671	8,556,630
Over-Allotment Option [Member] | Common Stock [Member]
Shares issued | shares		1,462,500		3,504,672
Underwriting discount | $				$ 8
Proceeds from issuance | $		$ 164		$ 367
Public Offering [Member] | Common Stock [Member]
Shares issued | shares		9,750,000		23,364,486
Shares issued (in usd per share)		$ 113.75		$ 107.00
Shares issued net of underwriting discount (in usd per share)		$ 111.87		$ 105.07
Settlement of Forward Sale Contracts [Member] | Common Stock [Member]
Underwriting discount | $		$ 3					$ 14	$ 16
Proceeds from issuance | $			$ 900				$ 800	$ 900
Forward sales price (in usd per share)						$ 104.53			$ 105.18
Sempra Energy [Member] | Series A Preferred Stock [Member]
Shares issued | shares				17,250,000
Conversion price (in usd per share)				$ 100.00
Stated rate of debt		6.00%
Conversion price net of underwriting discount (in usd per share)				98.20
Liquidation price (in usd per share)				$ 100.00
Proceeds from issuance | $					$ 1,690
Underwriting discount | $				$ 32
Shares issuable for each instrument | Rate		76.29%
Number of shares issuable | shares		13,200,000
Sempra Energy [Member] | Series B Preferred Stock [Member]
Shares issued | shares		5,750,000
Conversion price (in usd per share)		$ 100.00
Stated rate of debt		6.75%
Conversion price net of underwriting discount (in usd per share)		$ 98.35
Threshold appreciation price (in dollars per share)		136.50
Liquidation price (in usd per share)		$ 100.00
Proceeds from issuance | $		$ 566
Underwriting discount | $		$ 9
Number of shares issuable | shares		4,200,000
Share dividends issued, percentage of weighted average share price		97.00%
Sempra Energy [Member] | Over-Allotment Option [Member] | Series A Preferred Stock [Member]
Shares issued | shares				2,250,000
Sempra Energy [Member] | Over-Allotment Option [Member] | Series B Preferred Stock [Member]
Shares issued | shares		750,000
Subsequent Event [Member] | Settlement of Forward Sale Contracts [Member] | Common Stock [Member]
Shares issuable under forward contracts | shares	16,906,185
Minimum [Member] | Sempra Energy [Member] | Series B Preferred Stock [Member]
Threshold appreciation price (in dollars per share)		$ 113.75
Shares issuable for each instrument | Rate		73.26%
Maximum [Member] | Sempra Energy [Member] | Series B Preferred Stock [Member]
Threshold appreciation price (in dollars per share)		$ 136.50
Shares issuable for each instrument | Rate		87.91%

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