REGULATORY MATTERS (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended	24 Months Ended
	Mar. 31, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2019
San Diego Gas and Electric Company [Member]
Public Utilities, General Disclosures [Line Items]
Refund of 2015 memorandum account, After-tax		$ 9
Liability Associated With Tracked Income Tax Expense Differences	$ 3
San Diego Gas and Electric Company [Member] | California Public Utilities Commission [Member] | Capital Structure, Common Equity [Member]
Public Utilities, General Disclosures [Line Items]
Return on equity			10.30%
San Diego Gas and Electric Company [Member] | Forecast [Member] | California Public Utilities Commission [Member]
Public Utilities, General Disclosures [Line Items]
Reduced return on equity				10.20%
Southern California Gas Company [Member]
Public Utilities, General Disclosures [Line Items]
Refund of 2015 memorandum account, After-tax		$ 12
Liability Associated With Tracked Income Tax Expense Differences	$ 39
Southern California Gas Company [Member] | California Public Utilities Commission [Member] | Capital Structure, Common Equity [Member]
Public Utilities, General Disclosures [Line Items]
Return on equity			10.10%
Southern California Gas Company [Member] | Forecast [Member] | California Public Utilities Commission [Member]
Public Utilities, General Disclosures [Line Items]
Reduced return on equity				10.05%