GENERAL INFORMATION AND OTHER FINANCIAL DATA - CREDIT LOSSES (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 138	$ 29
Provisions for expected credit losses	96	84
Write-offs	(28)	(11)
Ending balance	206	103
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3	0
Reductions to expected credit losses	(2)	(3)
Ending balance	1	3
Allowance for credit losses	1	3
San Diego Gas and Electric Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	69	14
Provisions for expected credit losses	30	44
Write-offs	(16)	(6)
Ending balance	83	52
Southern California Gas Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	68	15
Provisions for expected credit losses	64	40
Write-offs	(12)	(5)
Ending balance	120	50
Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		1
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		$ 6
Allowance for credit losses
Accounts Receivable, Trade, Net [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	146
Accounts Receivable, Trade, Net [Member] | San Diego Gas and Electric Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	58
Accounts Receivable, Trade, Net [Member] | Southern California Gas Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	85
Accounts receivable – other, net [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	50
Accounts receivable – other, net [Member] | San Diego Gas and Electric Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	21
Accounts receivable – other, net [Member] | Southern California Gas Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	29
Other long-term assets [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	10
Other long-term assets [Member] | San Diego Gas and Electric Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	4
Other long-term assets [Member] | Southern California Gas Company [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	6
Due from Unconsolidated Affiliates - Noncurrent [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	1
Allowance for credit losses	1
Sempra LNG [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Maximum exposure under guarantor obligations			$ 4,000
Sempra LNG [Member] | Deferred Credits and Other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	7
Allowance for credit losses	$ 7