RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - DERIVATIVE INSTRUMENTS, EFFECT ON OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Investments, Fair Value Disclosure		$ 7,250		$ 7,250		$ 9,422
Derivatives in Net Investment Hedging Relationships | Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	[1],[2]	$ 34
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	[1],[2]		$ (222)	$ 53	$ (483)

[1] For the derivatives in net investment hedging relationships, the amount of gain/(loss) excluded from effectiveness testing, which was recognized in earnings, was $17 and $34 for the three months ended March 31, 2019 and 2018, respectively. The amount of gain/(loss) excluded from effectiveness testing was $44 and $107 for the nine months ended March 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 AOCI for such instruments was $226 and $(535), for the three months ended March 31, 2019 and 2018, respectively. The amount of gain/(loss) recognized in AOCI for such instruments was $467 and $(1,280), for the nine months ended March 31, 2019 and 2018, respectively.