Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Net amounts recognized	$ 309
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Pension assets	36	$ 8
Accrued pension liabilities	(264)	(327)
Net amounts recognized	(228)	(319)
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Accrued pension liabilities	(45)	(47)
Net amounts recognized	$ (45)	$ (47)