Debt (Schedule of credit facilities) (Details) $ in Billions	9 Months Ended
	Feb. 25, 2018 USD ($)
Line Of Credit Facility [Line Items]
Facility Amount	$ 11.9
Borrowed Amount	0.4
Committed Credit Facilities [Member]
Line Of Credit Facility [Line Items]
Facility Amount	11.4
Borrowed Amount	$ 0.2
Minimum fixed charge coverage ratio	2.5
Compliance with credit facility covenants	As of quarter end, we were in compliance with all of these covenants.
Line of Credit Expiring February 2019 [Member] | Bridge Loan [Member]
Line Of Credit Facility [Line Items]
Facility Amount	$ 8.5
Borrowed Amount	$ 0.0
Expiration date of credit facility	Feb. 28, 2019
Debt Instrument Term	364 days
Line of Credit Expiring May 2022 [Member]
Line Of Credit Facility [Line Items]
Facility Amount	$ 2.7
Borrowed Amount	$ 0.0
Expiration date of credit facility	May 31, 2022
Line of Credit Expiring June 2019 [Member]
Line Of Credit Facility [Line Items]
Facility Amount	$ 0.2
Borrowed Amount	$ 0.2
Expiration date of credit facility	Jun. 30, 2019
Uncommitted Credit Facilities [Member]
Line Of Credit Facility [Line Items]
Facility Amount	$ 0.5
Borrowed Amount	$ 0.2