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, 2018	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 420	$ 434	$ 423
Fair Value, Inputs, Level 1 and 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	3	2
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	3	2
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	417	432
Cash Equivalents [Member] | Fair Value, Inputs, Level 1 and 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	3	2
Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	3	2
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	299	310
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	60	64
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	44	46
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	$ 14	$ 12