INCOME TAXES (Summary of Operating Loss and Tax Credit Carryforward) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Federal
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 134
Federal | Pre-2018
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	3,600
Federal | Post-2017
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	24,887
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	25,364
Tax credit carryforward	$ 100