DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Derivative Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Net Amount Presented in the Consolidated Balance Sheets	$ 25	$ 37
Financial Instruments	0	0
Cash Collateral	24	37
Net Amount	1	0
Interest rate contracts - designated [Member]
Derivative [Line Items]
Net Amount Presented in the Consolidated Balance Sheets	0	0
Interest rate swaps - not designated [Member]
Derivative [Line Items]
Net Amount Presented in the Consolidated Balance Sheets	25	37
Financial Instruments	0	0
Cash Collateral	24	37
Net Amount	$ 1	$ 0