Pension and Other Postretirement Benefits - Schedule of Components of Periodic Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 38	$ 38
Interest cost	30	30
Pension benefits | Direct Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	38	38	$ 35
Interest cost	30	30	39
Expected return on plan assets	(50)	(50)	(55)
Amortization of deferred losses	31	44	28
Other	3	2	1
Net periodic benefit costs	52	64	48
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2
Interest cost	2	2
Postretirement benefits | Direct Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2
Interest cost	2	2	3
Expected return on plan assets	0	0	0
Amortization of deferred losses	1	1	1
Other	0	0	0
Net periodic benefit costs	$ 4	$ 5	$ 6