SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Millions			1 Months Ended	12 Months Ended
	Jan. 12, 2018 USD ($)	Jan. 09, 2018 USD ($) shares $ / shares Rate	Jan. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	[1]	Dec. 31, 2015 USD ($)	[1]	Dec. 29, 2017 $ / shares
Subsequent Event [Line Items]
Proceeds from issuance of shares				$ 47	$ 51		$ 52
Sempra Energy [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Share price (in dollars per share) | $ / shares									$ 106.92
Subsequent Event [Member] | Public Offering [Member]
Subsequent Event [Line Items]
Shares issued | shares		23,364,486
Subsequent Event [Member] | Over-Allotment Option [Member]
Subsequent Event [Line Items]
Shares issued | shares		3,504,672
Proceeds from issuance of shares		$ 368
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Shares issued | shares		26,869,158
Proceeds from issuance of shares		$ 2,460
Subsequent Event [Member] | Common Stock [Member] | Public Offering [Member]
Subsequent Event [Line Items]
Shares issued | shares		23,364,486
Price of shares issued (in dollars per share) | $ / shares		$ 107.00
Price of shares issued net of underwriting discount (in dollars per share) | $ / shares		$ 105.074
Subsequent Event [Member] | Common Stock [Member] | Over-Allotment Option [Member]
Subsequent Event [Line Items]
Shares issued | shares		3,504,672
Proceeds from issuance of shares		$ 368
Subsequent Event [Member] | Sempra Energy [Member] | Convertible Preferred Stock [Member]
Subsequent Event [Line Items]
Shares issued | shares		17,250,000	17,250,000
Stated percentage rate		6.00%
Conversion price per share (in dollars per share) | $ / shares		$ 100.00
Conversion price per share net of underwriting discount (in dollars per share) | $ / shares		98.20
Liquidation preference (in dollars per share) | $ / shares		100
Value of shares issued			$ 1,690
Threshold appreciation price (in dollars per share) | $ / shares		$ 131.075
Share dividends issued, percentage of weighted average share price		97.00%
Number of shares issuable | shares		16,100,000
Subsequent Event [Member] | Sempra Energy [Member] | Convertible Preferred Stock [Member] | Minimum [Member]
Subsequent Event [Line Items]
Threshold appreciation price (in dollars per share) | $ / shares		$ 107.00
Shares issuable for each instrument | Rate		76.29%
Subsequent Event [Member] | Sempra Energy [Member] | Convertible Preferred Stock [Member] | Maximum [Member]
Subsequent Event [Line Items]
Threshold appreciation price (in dollars per share) | $ / shares		$ 131.075
Shares issuable for each instrument | Rate		93.45%
Subsequent Event [Member] | Sempra Energy [Member] | Convertible Preferred Stock [Member] | Over-Allotment Option [Member]
Subsequent Event [Line Items]
Shares issued | shares		2,250,000
Energy Future Holdings Corp. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from issuance of debt	$ 4,900
Redemption price percentage	101.00%
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | Floating Rate Notes Due 2019 [Member]
Subsequent Event [Line Items]
Debt amount	$ 500
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | Floating Rate Notes Due 2019 [Member] | LIBOR [Member]
Subsequent Event [Line Items]
Variable percentage rate	0.25%
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | Floating Rate Notes Due 2021 [Member]
Subsequent Event [Line Items]
Debt amount	$ 700
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | Floating Rate Notes Due 2021 [Member] | LIBOR [Member]
Subsequent Event [Line Items]
Variable percentage rate	0.50%
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | 2.400% Senior Notes Due 2020 [Member]
Subsequent Event [Line Items]
Stated percentage rate	2.40%
Debt amount	$ 500
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | 2.900% Senior Notes Due 2023 [Member]
Subsequent Event [Line Items]
Stated percentage rate	2.90%
Debt amount	$ 500
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | 3.400% Senior Notes Due 2028 [Member]
Subsequent Event [Line Items]
Stated percentage rate	3.40%
Debt amount	$ 1,000
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | 3.800% Senior Notes Due 2038 [Member]
Subsequent Event [Line Items]
Stated percentage rate	3.80%
Debt amount	$ 1,000
Energy Future Holdings Corp. [Member] | Subsequent Event [Member] | 4.000% Senior Notes Due 2048 [Member]
Subsequent Event [Line Items]
Stated percentage rate	4.00%
Debt amount	$ 800

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