Retirement Benefits - Schedule of Information for Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets (Details) - Pension Plan - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 316	$ 3,778
Fair value of plan assets	$ 171	$ 3,502