INCOME TAXES - Tax Credit Carryforwards and Deferred Tax Assets (Details) $ in Millions	Sep. 30, 2019 USD ($)
Operating Loss Carryforwards [Line Items]
Net Operating Losses and Tax Credit Carryforwards	$ 230
Valuation Allowances on these Deferred Tax Assets	188
2020-2024
Operating Loss Carryforwards [Line Items]
Net Operating Losses and Tax Credit Carryforwards	14
Valuation Allowances on these Deferred Tax Assets	5
2025-2034
Operating Loss Carryforwards [Line Items]
Net Operating Losses and Tax Credit Carryforwards	30
Valuation Allowances on these Deferred Tax Assets	11
2035-2039
Operating Loss Carryforwards [Line Items]
Net Operating Losses and Tax Credit Carryforwards	11
Valuation Allowances on these Deferred Tax Assets	0
Indefinite
Operating Loss Carryforwards [Line Items]
Net Operating Losses and Tax Credit Carryforwards	175
Valuation Allowances on these Deferred Tax Assets	$ 172