SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - CASH AND CASH EQUIVALENTS AND RESTRICTED CASH (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Presentation Of Restricted Cash [Line Items]
Cash and cash equivalents	$ 108	$ 102
Restricted cash, current	31	35
Restricted cash, noncurrent	3	21
Cash, cash equivalents and restricted cash in discontinued operations	75	88
Cash, cash equivalents and restricted cash, including discontinued operations, December 31	217	246	$ 364	$ 425
San Diego Gas and Electric Company [Member]
Presentation Of Restricted Cash [Line Items]
Cash and cash equivalents	10	8
Restricted cash, current	0	11
Restricted cash, noncurrent	0	18
Total cash, cash equivalents and restricted cash on the Consolidated Statements of Cash Flows	$ 10	$ 37	$ 29	$ 20