RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - GAIN (LOSS) ON DERIVATIVE INSTRUMENTS (EFFECTIVE PORTION) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Foreign Exchange Contract | Derivatives in Net Investment Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	[1],[2]	$ 23	$ (89)	$ 19	$ (262)

[1] For the derivatives in net investment hedging relationships, the amount of gain/(loss) excluded from effectiveness testing, which was recognized in earnings, was $13 and $42 for the three months ended December 31, 2018 and 2017, respectively. The amount of gain/(loss) excluded from effectiveness testing was $27 and $73 for the six months ended December 31, 2018 and 2017, 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 AOCI for such instruments was $228 and $(176), for the three months ended December 31, 2018 and 2017, respectively. The amount of gain/(loss) recognized in AOCI for such instruments was $241 and $(745), for the six months ended December 31, 2018 and 2017, respectively.