Pension and Other Postretirement Benefits - Schedule of Funded and Unfunded Pension Plans (Details) - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Grantor Trust assets	$ 266	$ 276
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	1,119	1,172	$ 1,203
Accumulated benefit obligation	1,010	1,040
Fair value of plan assets	891	853	$ 801
Grantor Trust assets	266	276
Funded plans \| Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	855	901
Accumulated benefit obligation	747	777
Fair value of plan assets	891	853
Unfunded plans \| Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	264	271
Accumulated benefit obligation	260	267
Fair value of plan assets	$ 0	$ 0

The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations.

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Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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