REVENUES - RECEIVABLES FROM REVENUES FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	$ 1,350	$ 1,462
Accounts receivable – trade, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	1,216	1,447
Accounts receivable – other, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	17	12
Due from unconsolidated affiliates – current [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	2	3
Other long-term assets [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	115	0
San Diego Gas and Electric Company [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	703	583
San Diego Gas and Electric Company [Member] | Accounts receivable – trade, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	642	573
San Diego Gas and Electric Company [Member] | Accounts receivable – other, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	11	8
San Diego Gas and Electric Company [Member] | Due from unconsolidated affiliates – current [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	3	2
San Diego Gas and Electric Company [Member] | Other long-term assets [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	47	0
Southern California Gas Company [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	536	790
Southern California Gas Company [Member] | Accounts receivable – trade, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	462	786
Southern California Gas Company [Member] | Accounts receivable – other, net [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	6	4
Southern California Gas Company [Member] | Other long-term assets [Member]
Contract with Customer, Asset [Line Items]
Receivables from revenues from contracts with customers	$ 68	$ 0