Shareholders' Equity (Narrative) (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended			36 Months Ended
	Mar. 21, 2018 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares
Class of Stock [Line Items]
Common shares, authorized		755,000,000	755,000,000		755,000,000
Preferred shares, authorized		500,000	500,000		500,000
Treasury shares acquired | $		$ 350	$ 600	$ 550
Payments for Repurchase of Common Stock | $		350	600	550
Retained earnings decrease | $		(1,170)	(5,434)		$ (1,170)
Treasury Shares
Class of Stock [Line Items]
Treasury shares acquired | $		$ 350	$ 600	$ 550	$ 1,500
Treasury Stock, Shares, Acquired		7,300,000	11,000,000	8,400,000
Payments for Repurchase of Common Stock | $		$ 350
Treasury shares acquired, average price per share (in usd per share) | $ / shares		$ 48.00	$ 52.32	$ 65.30
Treasury Stock Acquired Shares			11,500,000
Common Class A
Class of Stock [Line Items]
Common shares, authorized		750,000,000	750,000,000		750,000,000
Common Stock, Voting Rights, Votes		1
Common Class B
Class of Stock [Line Items]
Common shares, authorized		5,000,000	5,000,000		5,000,000
Common Stock, Voting Rights, Votes		0.2
Accelerated share repurchase plan | Treasury Shares
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired	4,300,000
Payments for Repurchase of Common Stock | $	$ 300
Treasury shares acquired, average price per share (in usd per share) | $ / shares	$ 69.26