Acquisition and Divestitures (Acquisition Purchase Accounting Table) (Details) - USD ($) $ in Millions	May 27, 2018	May 28, 2017	May 29, 2016	May 31, 2015
Acquired Assets and Assumed Liabilities [Abstract]
Goodwill	$ 14,065.0	$ 8,747.2	$ 8,741.2	$ 8,874.9
Business Acquisition, Blue Buffalo [Member]
Acquired Assets and Assumed Liabilities [Abstract]
Receivables	128.9
Inventories	176.5
Prepaid expenses and other current assets	4.8
Land, buildings, and equipment	359.2
Goodwill	5,294.9
Other intangible assets	3,015.0
Other assets	1.7
Accounts payable	(55.1)
Other current liabilities	(62.2)
Deferred income taxes	(750.2)
Other liabilities	(77.7)
Total assets acquired and liabilities assumed	$ 8,035.8