RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - DERIVATIVE INSTRUMENTS, EFFECT ON OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Derivatives in Net Investment Hedging Relationships | Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	[1],[2]	$ (82)	$ 23	$ 31	$ 19

[1] For the derivatives in net investment hedging relationships, the amount of gain/(loss) excluded from effectiveness testing, which was recognized in earnings, was $21 and $13 for the three months ended December 31, 2019 and 2018, respectively. The amount of gain/(loss) excluded from effectiveness testing was $40 and $27 for the six months ended December 31, 2019 and 2018, respectively.

[2] In addition to the foreign currency derivative contracts designated as net investment hedges, certain of our foreign currency denominated debt instruments are designated as net investment hedges. The amount of gain/(loss) recognized in Accumulated other comprehensive income/(loss) (AOCI) for such instruments was $(428) and $228 for the three months ended December 31, 2019 and 2018, respectively. The amount of gain/(loss) recognized in AOCI for such instruments was $181 and $241 for the six months ended December 31, 2019 and 2018, respectively.