INCOME TAXES - DEFERRED INCOME TAXES (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets, Gross [Abstract]
Less: valuation allowances	$ 133	$ 31
Deferred income taxes, noncurrent	170	234	[1]
Deferred income tax liabilities, noncurrent	2,767	3,745	[1]
Sempra Energy Consolidated [Member]
Deferred Tax Liabilities, Gross [Abstract]
Differences in financial and tax bases of fixed assets, investments and other assets	4,233	6,111
U.S. state and non-U.S. withholding tax on repatriation of foreign earnings	360	0
Regulatory balancing accounts	376	783
Property taxes	37	63
Other deferred income tax liabilities	117	143
Total deferred income tax liabilities	5,123	7,100
Deferred Tax Assets, Gross [Abstract]
Tax credits	1,066	431
Net operating losses	968	2,304
Compensation-related items	199	252
Postretirement benefits	251	434
Other deferred income tax assets	115	87
Accrued expenses not yet deductible	60	112
Deferred income tax assets before valuation allowances	2,659	3,620
Less: valuation allowances	133	31
Total deferred income tax assets	2,526	3,589
Net deferred income tax liability	2,597	3,511
Deferred income taxes, noncurrent	170	234
Deferred income tax liabilities, noncurrent	2,767	3,745
San Diego Gas and Electric Company [Member]
Deferred Tax Liabilities, Gross [Abstract]
Differences in financial and tax bases of fixed assets, investments and other assets	1,472	2,549
Regulatory balancing accounts	113	379
Property taxes	26	42
Other deferred income tax liabilities	10	10
Total deferred income tax liabilities	1,621	2,980
Deferred Tax Assets, Gross [Abstract]
Tax credits	7	27
Net operating losses	0	0
Compensation-related items	5	8
Postretirement benefits	43	98
Other deferred income tax assets	19	11
State income taxes	14	0
Accrued expenses not yet deductible	3	7
Total deferred income tax assets	91	151
Net deferred income tax liability	1,530	2,829
Deferred income tax liabilities, noncurrent	1,530	2,829	[1]
Southern California Gas Company [Member]
Deferred Tax Liabilities, Gross [Abstract]
Differences in financial and tax bases of fixed assets, investments and other assets	987	1,699
Regulatory balancing accounts	271	411
Property taxes	12	21
Other deferred income tax liabilities	1	4
Total deferred income tax liabilities	1,271	2,135
Deferred Tax Assets, Gross [Abstract]
Tax credits	15	17
Net operating losses	58	83
Compensation-related items	25	32
Postretirement benefits	152	244
Other deferred income tax assets	7	11
State income taxes	7	19
Accrued expenses not yet deductible	12	20
Total deferred income tax assets	276	426
Net deferred income tax liability	995	1,709
Deferred income tax liabilities, noncurrent	$ 995	$ 1,709	[1]

[1] Reflects reclassifications to conform to current year presentation, which we discuss in Note 1.