COMMITMENTS AND CONTINGENCIES - OTHER LITIGATION (Details) £ in Millions, $ in Millions	1 Months Ended		3 Months Ended
	Oct. 31, 2020 GBP (£)	Mar. 31, 2020 GBP (£)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Apr. 30, 2021 claim lawsuit	Oct. 01, 2014 GBP (£)	Oct. 01, 2014 USD ($)
R B S Sempra Commodities [Member] | HMRC VAT Claim [Member]
Loss Contingencies [Line Items]
VAT tax claim paid upon appeal						£ 86	$ 138
Plaintiffs [Member] | HMRC VAT Claim [Member]
Loss Contingencies [Line Items]
Damages awarded		£ 45	$ 62
Cost and interest assessed	£ 21		$ 29
Energy Future Holdings Corp. [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit					4
Number of proof of claims | claim					28,000
R B S Sempra Commodities [Member]
Loss Contingencies [Line Items]
Equity losses on investment | $				$ 100
Maximum [Member] | R B S Sempra Commodities [Member] | HMRC VAT Claim [Member]
Loss Contingencies [Line Items]
VAT tax claim, penalty (as a percentage)						100.00%	100.00%