RELATED PARTY TRANSACTIONS - Summary of Related Party Receivables (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Related party receivable	$ 25	$ 221
Affiliated Entity
Related Party Transaction [Line Items]
Related party receivable	25	221
Due from Parent cash pool \| Affiliated Entity
Related Party Transaction [Line Items]
Related party receivable	0	202
Professional services provided to Parent / other \| Affiliated Entity
Related Party Transaction [Line Items]
Related party receivable	$ 25	$ 19

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

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+ Details