RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - NOTIONAL AMOUNTS AND FAIR VALUES OF QUALIFYING AND NON-QUALIFYING FINANCIAL INSTRUMENTS USED IN HEDGING TRANSACTIONS - ADDITIONAL INFORMATION (Details) - Underlying, Other - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Fair Value Hedging
Derivative [Line Items]
Underlying Debt Obligation, Carrying Amount	$ 7,400	$ 7,900
Net Investment Hedging
Derivative [Line Items]
Underlying Debt Obligation, Carrying Amount	$ 16,000	$ 17,200