RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - GAIN (LOSS) ON DERIVATIVE INSTRUMENTS (EFFECTIVE PORTION) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
|---|---|---|
Sep. 30, 2016 |
Jun. 30, 2016 |
|
| Derivatives in Cash Flow Hedging Relationships | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain/(Loss) Recognized in AOCI on Derivatives (Effective Portion) | $ (4) | $ (2) |
| Derivatives in Cash Flow Hedging Relationships | Interest Rate Contracts | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain/(Loss) Recognized in AOCI on Derivatives (Effective Portion) | (2) | (2) |
| Derivatives in Cash Flow Hedging Relationships | Foreign Currency Contracts | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain/(Loss) Recognized in AOCI on Derivatives (Effective Portion) | (2) | 0 |
| Derivatives in Net Investment Hedging Relationships | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain/(Loss) Recognized in AOCI on Derivatives (Effective Portion) | $ (74) | $ (53) |