OTHER FINANCIAL DATA - INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense	$ (84)	$ 282	$ 378	$ 284
Effective income tax rate	(560.00%)	29.00%	32.00%	21.00%
Impairment of wildfire regulatory asset	$ 351	$ 0	$ 351	$ 0
Remeasurement of equity method investment	0	617	0	617
Income tax expense from transactional effects of foreign currency and inflation	12		137
Income tax expense from transactional effects of foreign currency and inflation net of noncontrolling interest	8		91
Gain (loss) from foreign currency derivatives	4		101
Gain (loss) from foreign currency derivatives after-tax	2		61
San Diego Gas and Electric Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense	$ (72)	$ 91	$ 72	$ 204
Effective income tax rate	79.00%	32.00%	20.00%	33.00%
Impairment of wildfire regulatory asset	$ 351		$ 351	$ 0
Southern California Gas Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense	$ (14)	$ 21	$ 103	$ 75
Effective income tax rate	200.00%	100.00%	28.00%	27.00%
Sempra Mexico [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Remeasurement of equity method investment				$ 617