OTHER FINANCIAL DATA - GREENHOUSE GAS ALLOWANCES (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Abstract]
Sundry	$ 3,569	$ 3,414	[1]
Greenhouse Gas Allowance [Member]
Regulatory Assets [Abstract]
Other current assets	40	40
Sundry	334	295
Total assets	374	335
Greenhouse Gas Obligation [Member]
Regulatory LIabilities [Abstract]
Other current liabilities	40	40
Deferred credits and other	202	171
Total liabilities	242	211
San Diego Gas and Electric Company [Member]
Regulatory Assets [Abstract]
Other current assets	104	81	[1]
Sundry	1,004	998	[1]
San Diego Gas and Electric Company [Member] | Greenhouse Gas Allowance [Member]
Regulatory Assets [Abstract]
Other current assets	16	16
Sundry	190	182
Total assets	206	198
San Diego Gas and Electric Company [Member] | Greenhouse Gas Obligation [Member]
Regulatory LIabilities [Abstract]
Other current liabilities	16	16
Deferred credits and other	88	72
Total liabilities	104	88
Southern California Gas Company [Member]
Regulatory Assets [Abstract]
Other current assets	8	8	[1]
Sundry	679	589	[1]
Southern California Gas Company [Member] | Greenhouse Gas Allowance [Member]
Regulatory Assets [Abstract]
Other current assets	24	24
Sundry	140	109
Total assets	164	133
Southern California Gas Company [Member] | Greenhouse Gas Obligation [Member]
Regulatory LIabilities [Abstract]
Other current liabilities	24	24
Deferred credits and other	111	96
Total liabilities	$ 135	$ 120

[1] Derived from audited financial statements.