SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - OTHER INCOME, NET (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Other Income [Line Items]
Allowance for equity funds used during construction	$ 98	$ 168		$ 116
Investment (losses) gains	(6)	56		23
Gains (losses) on interest rate and foreign exchange instruments, net	7	47		(32)
Foreign currency transaction losses	(5)	(35)		(1)
Non-service component of net periodic benefit (cost) credit	(37)	(21)		6
Electrical infrastructure relocation income	7	3		10
Interest on regulatory balancing accounts, net	2	3		4
Sundry, net	6	12		12
Total	72	233	[1]	138	[1]
San Diego Gas and Electric Company [Member]
Other Income [Line Items]
Allowance for equity funds used during construction	61	63		46
Non-service component of net periodic benefit (cost) credit	(6)	4		14
Interest on regulatory balancing accounts, net	4	3		3
Sundry, net	(3)	0		1
Total	56	70	[1]	64	[1]
Southern California Gas Company [Member]
Other Income [Line Items]
Allowance for equity funds used during construction	36	44		40
Non-service component of net periodic benefit (cost) credit	(10)	(5)		6
Interest on regulatory balancing accounts, net	(2)	0		1
Sundry, net	(9)	(8)		(9)
Total	15	31	[1]	$ 38	[1]
Sempra Mexico [Member] | IMG [Member]
Other Income [Line Items]
Foreign currency transaction losses	$ (3)	$ (35)

[1] As adjusted for the retrospective adoption of ASU 2017-07, which we discuss in Note 2, and a reclassification to conform to current year presentation, which we discuss in Note 1.