GENERAL INFORMATION AND OTHER FINANCIAL DATA - WILDFIRE FUND (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019		Sep. 30, 2019
Loss Contingencies [Line Items]
Current portion of the Wildfire Fund asset	$ 29.0	$ 29.0	$ 29.0
Noncurrent portion of the Wildfire Fund asset	378.0	378.0	392.0	[1]
Wildfire Fund obligation in other current liabilities	13.0	13.0	13.0
Wildfire Fund obligation in deferred credits and other	87.0	$ 87.0	86.0
Wildfire fund asset, amortization expense	7.0		14.0
Wildfire fund obligation, accretion expense	1.0		1.0
San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Wildfire Fund asset					$ 451.5
Estimated period of benefit		15 years
Noncurrent portion of the Wildfire Fund asset	$ 378.0	$ 378.0	$ 392.0	[1]

[1] Derived from audited financial statements.