EMPLOYEE BENEFIT PLANS (Retirement Income Plan's Assets Carried at Fair Value) (Details) - Retirement Income Plans [Member] - Other Postretirement Benefits Plan [Member] - USD ($) $ in Millions	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 485	$ 420	$ 434
Fair Value, Inputs, Level 1 and 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	2	3
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	2	3
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	483	417
Cash Equivalents [Member] | Fair Value, Inputs, Level 1 and 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	2	3
Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	2	3
Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Bond Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	393	299
International Equity Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	50	60
Domestic Equity Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	39	44
Defined Benefit Plan, Real Estate [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 1	$ 14