EMPLOYEE BENEFITS (Amounts in AOCI not Recognized as Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Total plans, at the beginning of period	$ (14.3)	$ (0.8)
Total - Recognition of net periodic benefits expense	(0.2)	0.3
Total plans - Deferrals	(1.0)	(13.8)
Total plans - Net Change in AOCI	(1.2)	(13.5)
Total plans, at the end of period	(15.5)	(14.3)
Pension Plans
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss, at the beginning of period	(11.2)
Prior service benefit/(cost), at the beginning of period	(7.4)
Deferred income tax (expense)/benefit, at the beginning of period	5.5
Total plans, at the beginning of period	(13.1)
Prior service benefit/(cost) - Recognition of net periodic benefits expense	(0.2)	0.4
Deferred income tax (expense)/benefit - Recognition of net periodic benefits expense		(0.1)
Total - Recognition of net periodic benefits expense	(0.2)	0.3
Net actuarial loss - Deferrals	(0.4)	(11.2)
Prior service benefit/(cost) - Deferrals		(7.8)
Deferred income tax (expense)/benefit - Deferrals	0.2	5.6
Total plans - Deferrals	(0.2)	(13.4)
Net actuarial loss - Net Change in AOCI	(0.4)	(11.2)
Prior service benefit/(cost) - Net Change in AOCI	(0.2)	(7.4)
Deferred income tax (expense)/benefit - Net Change in AOCI	0.2	5.5
Total plans - Net Change in AOCI	(0.4)	(13.1)
Net actuarial loss, at the end of period	(11.6)	(11.2)
Prior service benefit/(cost), at the end of period	(7.6)	(7.4)
Deferred income tax (expense)/benefit, at the end of period	5.7	5.5
Total plans, at the end of period	(13.5)	(13.1)
OPEB Plans
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss, at the beginning of period	(1.6)	(1.2)
Deferred income tax (expense)/benefit, at the beginning of period	0.4	0.4
Total plans, at the beginning of period	(1.2)	(0.8)
Net actuarial loss - Deferrals	(0.8)	(0.4)
Total plans - Deferrals	(0.8)	(0.4)
Net actuarial loss - Net Change in AOCI	(0.8)	(0.4)
Total plans - Net Change in AOCI	(0.8)	(0.4)
Net actuarial loss, at the end of period	(2.4)	(1.6)
Deferred income tax (expense)/benefit, at the end of period	0.4	0.4
Total plans, at the end of period	$ (2.0)	$ (1.2)