Financial Instruments, Risk Management Activities, and Fair Values (Schedule of fair value measurement inputs) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Nov. 23, 2014	May 25, 2014
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	$ 15.3	$ 30.3
Other Assets Fair Value Disclosure	255.4	326.0
Total Assets Fair Value Disclosure	287.7	363.8
Derivative Liability Fair Value	36.9	23.1
Other Liabilities Fair Value Disclosure	0	0
Total Liabilities Fair Value Disclosure	(44.2)	(28.0)
Book value	3,824.2	3,941.9
Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	13.1	10.6
Derivative Liability Fair Value	(10.9)	(12.6)
Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	19.2	27.2
Derivative Liability Fair Value	(33.3)	(15.4)
Fair Value Inputs Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	7.6	7.2
Total Assets Fair Value Disclosure	7.9	18.3
Other Liabilities Fair Value Disclosure	0	0
Total Liabilities Fair Value Disclosure	0	0
Fair Value Inputs Level 1 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.3	11.1
Derivative Liability Fair Value	0	0
Fair Value Inputs Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	247.8	318.8
Total Assets Fair Value Disclosure	279.8	345.5
Other Liabilities Fair Value Disclosure	0	0
Total Liabilities Fair Value Disclosure	(44.2)	(28.0)
Fair Value Inputs Level 2 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	13.1	10.6
Derivative Liability Fair Value	(10.9)	(12.6)
Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	18.9	16.1
Derivative Liability Fair Value	(33.3)	(15.4)
Fair Value Inputs Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	0	0
Total Assets Fair Value Disclosure	0	0
Other Liabilities Fair Value Disclosure	0	0
Total Liabilities Fair Value Disclosure	0	0
Fair Value Inputs Level 3 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Marketable Investments [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	255.4	326.0
Other Liabilities Fair Value Disclosure	0	0
Marketable Investments [Member] | Fair Value Inputs Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	7.6	7.2
Other Liabilities Fair Value Disclosure	0	0
Marketable Investments [Member] | Fair Value Inputs Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	247.8	318.8
Other Liabilities Fair Value Disclosure	0	0
Marketable Investments [Member] | Fair Value Inputs Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Assets Fair Value Disclosure	0	0
Other Liabilities Fair Value Disclosure	0	0
Long-Lived Assets [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Non-cash impairment charge	15.2
Book value	26.7
Long-Lived Assets [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	11.5
Derivative Liability Fair Value	0
Long-Lived Assets [Member] | Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	0
Long-Lived Assets [Member] | Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	11.5
Derivative Liability Fair Value	0
Long-Lived Assets [Member] | Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	0
Interest Rate Contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.5	0.7
Derivative Liability Fair Value	2.5	0
Interest Rate Contracts [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.5	0.7
Derivative Liability Fair Value	(2.5)	0
Interest Rate Contracts [Member] | Fair Value Inputs Level 1 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Interest Rate Contracts [Member] | Fair Value Inputs Level 2 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.5	0.7
Derivative Liability Fair Value	(2.5)	0
Interest Rate Contracts [Member] | Fair Value Inputs Level 3 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Foreign Exchange Contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	14.1	10.5
Derivative Liability Fair Value	13.3	19.1
Foreign Exchange Contracts [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	12.6	9.9
Derivative Liability Fair Value	(8.4)	(12.6)
Foreign Exchange Contracts [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	1.5	0.6
Derivative Liability Fair Value	(4.9)	(6.5)
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 1 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 2 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	12.6	9.9
Derivative Liability Fair Value	(8.4)	(12.6)
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	1.5	0.6
Derivative Liability Fair Value	(4.9)	(6.5)
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 3 [Member] | Designated as Hedging Instrument [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Foreign Exchange Contracts [Member] | Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Equity Contracts [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	(0.5)
Equity Contracts [Member] | Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	0
Equity Contracts [Member] | Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	(0.5)
Equity Contracts [Member] | Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0
Derivative Liability Fair Value	0
Commodity Contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.7	19.1
Derivative Liability Fair Value	21.1	4.0
Commodity Contracts [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.7	19.1
Derivative Liability Fair Value	(21.1)	(4.0)
Commodity Contracts [Member] | Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.3	11.1
Derivative Liability Fair Value	0	0
Commodity Contracts [Member] | Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0.4	8.0
Derivative Liability Fair Value	(21.1)	(4.0)
Commodity Contracts [Member] | Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Grain Contracts [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	5.5	7.5
Derivative Liability Fair Value	(6.8)	(4.9)
Grain Contracts [Member] | Fair Value Inputs Level 1 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	0	0
Grain Contracts [Member] | Fair Value Inputs Level 2 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	5.5	7.5
Derivative Liability Fair Value	(6.8)	(4.9)
Grain Contracts [Member] | Fair Value Inputs Level 3 [Member] | Not Designated as Hedging [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative Asset Fair Value	0	0
Derivative Liability Fair Value	$ 0	$ 0