DERIVATIVES (Outstanding Derivative Balances) (Details) - Commodity Risk - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	$ (83)	$ (73)
Derivative Asset, Netting	0	0
Cash Collateral	125	140
Total Derivative Balance, Assets	42	67
Current assets – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	50	33
Derivative Asset, Netting	(3)	0
Cash Collateral	105	115
Total Derivative Balance, Assets	152	148
Noncurrent assets – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	136	136
Derivative Asset, Netting	0	0
Cash Collateral	0	0
Total Derivative Balance, Assets	136	136
Current liabilities – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Liabilities	(41)	(38)
Derivative Liability, Netting	3	0
Cash Collateral	17	15
Total Derivative Balance, Liabilities	(21)	(23)
Noncurrent liabilities – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Liabilities	(228)	(204)
Derivative Liability, Netting	0	0
Cash Collateral	3	10
Total Derivative Balance, Liabilities	$ (225)	$ (194)