Pension and Other Postretirement Benefits - Schedule of Projected Benefit Obligation, Changes in Fair Value of Plan Assets and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Change in the fair value of plan assets for the Company’s benefit plans:
Grantor Trust assets	$ 276	$ 270
Pension benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year	1,203	1,468
Service cost	30	38
Interest cost	52	30
Benefits paid	(22)	(22)
Settlements	(32)	(56)
Actuarial gains	(58)	(256)
Other	(1)	1
Projected benefit obligation, end of the year	1,172	1,203
Change in the fair value of plan assets for the Company’s benefit plans:
Fair value of plan assets, beginning of the year	801	972
Actual return on plan assets	53	(152)
Employer contributions	53	59
Benefits paid	(22)	(22)
Settlements	(32)	(56)
Fair value of plan assets, end of the year	853	801
Funded status	(319)	(402)
Grantor Trust assets	276	270
Postretirement benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year	53	98
Service cost	1	1
Interest cost	2	2
Benefits paid	(4)	(4)
Settlements	0	0
Actuarial gains	(5)	(46)
Other	0	2
Projected benefit obligation, end of the year	47	53
Change in the fair value of plan assets for the Company’s benefit plans:
Fair value of plan assets, beginning of the year	0	0
Actual return on plan assets	0	0
Employer contributions	4	4
Benefits paid	(4)	(4)
Settlements	0	0
Fair value of plan assets, end of the year	0	0
Funded status	(47)	(53)
Grantor Trust assets	$ 0	$ 0