Financial Instruments, Risk Management Activities, and Fair Values (Schedule of interest rate derivatives) (Details) - Interest Rate Contracts [Member] - USD ($) $ in Millions	May 29, 2016	May 31, 2015
Derivative [Line Items]
Derivative, Notional Amount	$ 1,000.0	$ 1,250.0
Average Receive Rate	1.80%	1.60%
Average Pay Rate	1.10%	0.70%
Swap Contract Maturities, Year Two	$ 500.0
Swap Contract Maturities, Year Four	500.0
Swap Contract Maturities, Total	$ 1,000.0