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, 2019	Jun. 30, 2018
Change in the fair value of plan assets for the Company's benefit plans:
Grantor Trust assets		$ 249	$ 265
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year		322	350
Service cost		19	2
Interest cost		30	10
Benefits paid		(17)	(12)
Settlements	[1]	(16)	(21)
Actuarial losses (gains)	[2]	148	(7)
Liabilities assumed from 21CF		765	0
Other		4	0
Projected benefit obligation, end of the year		1,255	322
Change in the fair value of plan assets for the Company's benefit plans:
Fair value of plan assets, beginning of the year		70	70
Actual return on plan assets		50	3
Employer contributions		83	30
Benefits paid		(17)	(12)
Settlements	[1]	(16)	(21)
Assets received from 21CF		630	0
Fair value of plan assets, end of the year		800	70
Funded status	[3]	(455)	(252)
Grantor Trust assets	[3]	249	265
Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of the year		0	0
Service cost		1	0
Interest cost		2	0
Benefits paid		(1)	0
Settlements	[1]	0	0
Actuarial losses (gains)	[2]	4	0
Liabilities assumed from 21CF		98	0
Other		(1)	0
Projected benefit obligation, end of the year		103	0
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		1	0
Benefits paid		(1)	0
Settlements	[1]	0	0
Assets received from 21CF		0	0
Fair value of plan assets, end of the year		0	0
Funded status	[3]	(103)	0
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, 2019 and 2018 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. Prior to the Distribution, the assets of the Grantor Trust were held by an irrevocable grantor trust of 21CF (the “21CF Grantor Trust”).