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, 2020	Jun. 30, 2019
Change in the fair value of plan assets for the Company's benefit plans:
Grantor Trust assets		$ 247	$ 249
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year		1,255	322
Service cost		35	19
Interest cost		39	30
Benefits paid		(21)	(17)
Settlements	[1]	(45)	(16)
Actuarial losses (gains)	[2]	145	148
Liabilities assumed from 21CF		0	765
Other		1	4
Projected benefit obligation, end of the year		1,409	1,255
Change in the fair value of plan assets for the Company's benefit plans:
Fair value of plan assets, beginning of the year		800	70
Actual return on plan assets		24	50
Employer contributions		30	83
Benefits paid		(21)	(17)
Settlements	[1]	(45)	(16)
Assets received from 21CF		0	630
Fair value of plan assets, end of the year		788	800
Funded status	[3]	(621)	(455)
Grantor Trust assets	[3]	247	249
Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year		103	0
Service cost		2	1
Interest cost		3	2
Benefits paid		(3)	(1)
Settlements	[1]	0	0
Actuarial losses (gains)	[2]	(1)	4
Liabilities assumed from 21CF		0	98
Other		0	(1)
Projected benefit obligation, end of the year		104	103
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		3	1
Benefits paid		(3)	(1)
Settlements	[1]	0	0
Assets received from 21CF		0	0
Fair value of plan assets, end of the year		0	0
Funded status	[3]	(104)	(103)
Grantor Trust assets	[3]	$ 0	$ 0

[1] Represents the full settlement of former employees deferred pension benefit obligations through lump sum payments.

[2] The actuarial losses (gains) for June 30, 2020 and 2019 were mainly due to a change in the discount rate assumption utilized in measuring plan obligations.

[3] The Company has established an irrevocable grantor trust (the “Grantor Trust”), administered by an independent trustee, with the intention of making cash contributions to the Trust to fund certain future pension benefit obligations of the Company. The assets in the Grantor Trust are unsecured funds of the Company and can be used to satisfy the Company’s obligations in the event of bankruptcy or insolvency.