Investments in Unconsolidated Joint Ventures (Schedule of combined financial information for the joint ventures on a 100% basis) (Details) - USD ($) $ in Millions	12 Months Ended
	May 28, 2017	May 29, 2016	May 31, 2015
Schedule of Equity Method Investments [Line Items]
Net sales	$ 2,083.5	$ 2,044.2	$ 2,264.7
Gross margin	865.9	867.6	925.4
Earnings before income taxes	243.3	234.8	220.9
Earnings after income taxes	190.3	186.7	170.7
Current assets	849.7	814.1
Noncurrent assets	858.9	959.9
Current liabilities	1,469.6	1,457.3
Noncurrent liabilities	55.2	81.7
Cereal Partners Worldwide [Member]
Schedule of Equity Method Investments [Line Items]
Net sales	1,648.4	1,674.8	1,894.5
Haagen Dazs Japan [Member]
Schedule of Equity Method Investments [Line Items]
Net sales	$ 435.1	$ 369.4	$ 370.2