RETIREMENT BENEFIT OBLIGATIONS - Schedule of Allocation of Plan Assets (Details) - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 911	$ 886	$ 933
NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	304	281
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16	8
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	585	591
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	6	$ 6
Domestic equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35	42
Domestic equity funds \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35	42
Domestic equity funds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Domestic equity funds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Domestic equity funds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39	69
International equity funds \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20	33
International equity funds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equity funds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	36
International equity funds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Domestic fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	111	104
Domestic fixed income funds \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	111	104
Domestic fixed income funds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Domestic fixed income funds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Domestic fixed income funds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	652	606
International fixed income funds \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	119	86
International fixed income funds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International fixed income funds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	533	520
International fixed income funds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Balanced funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28	35
Balanced funds \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Balanced funds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Balanced funds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28	35
Balanced funds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	46	30
Other \| NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	16
Other \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16	8
Other \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	0
Other \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 6	$ 6