Pension and Other Postretirement Benefits - Funded and Unfunded Pension Plans (Details) - USD ($) $ in Millions	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Grantor Trust assets	$ 270	$ 304
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Net amounts recognized	1,203	1,468	$ 1,409
Accumulated benefit obligation	1,069	1,319
Fair value of plan assets	801	972	$ 788
Grantor Trust assets	270	304
Funded Plans | Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Net amounts recognized	930	1,150
Accumulated benefit obligation	801	1,010
Fair value of plan assets	801	972
Unfunded Plans | Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Net amounts recognized	273	318
Accumulated benefit obligation	268	309
Fair value of plan assets	$ 0	$ 0