Financial Instruments, Risk Management Activities, and Fair Values (Schedule of fair value measurement inputs) (Details) - USD ($) | Nov. 25, 2014 | May. 31, 2015 | May. 31, 2015 | May. 25, 2014 | May. 26, 2013 | May. 27, 2012 |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | $ 40,000,000 | $ 40,000,000 | $ 30,300,000 | | |
Other Assets, Fair Value Disclosure | | 203,000,000 | 203,000,000 | 326,000,000 | | |
Total Assets, Fair Value Disclosure | | 246,300,000 | 246,300,000 | 363,800,000 | | |
Derivative Liability, Fair Value | | (124,700,000) | (124,700,000) | (23,100,000) | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Total Liabilities, Fair Value Disclosure | | (132,500,000) | (132,500,000) | (28,000,000) | | |
Book value of long-lived assets | | 3,783,300,000 | 3,783,300,000 | 3,941,900,000 | | |
Proceeds from sale of long-lived assets | | | 11,000,000 | 6,600,000 | $ 24,200,000 | |
Non-cash impairment charge of indefinite-lived intangible assets | $ 0 | | 260,000,000 | | | |
Book value of indefinite-lived intangible assets | | 4,677,000,000 | 4,677,000,000 | 5,014,300,000 | $ 5,015,100,000 | $ 4,704,900,000 |
Long-Lived Assets [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 37,800,000 | 37,800,000 | | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | | | |
Non-cash impairment charge of long-lived assets | | | 30,300,000 | | | |
Book value of long-lived assets | | 68,100,000 | 68,100,000 | | | |
Indefinite-lived Intangible Asset [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 154,300,000 | 154,300,000 | | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | | | |
Green Giant [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Non-cash impairment charge of indefinite-lived intangible assets | | 260,000,000 | 260,000,000 | | | |
Book value of indefinite-lived intangible assets | $ 425,900,000 | | | | | |
Green Giant [Member] | Indefinite-lived Intangible Asset [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 154,300,000 | 154,300,000 | | | |
Non-cash impairment charge of indefinite-lived intangible assets | | | 260,000,000 | | | |
Book value of indefinite-lived intangible assets | | 414,300,000 | 414,300,000 | | | |
Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 29,500,000 | 29,500,000 | 10,600,000 | | |
Derivative Liability, Fair Value | | (23,300,000) | (23,300,000) | (12,600,000) | | |
Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 13,800,000 | 13,800,000 | 27,200,000 | | |
Derivative Liability, Fair Value | | (109,200,000) | (109,200,000) | (15,400,000) | | |
Level 1 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 8,300,000 | 8,300,000 | 7,200,000 | | |
Total Assets, Fair Value Disclosure | | 15,500,000 | 15,500,000 | 18,300,000 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Total Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Level 1 [Member] | Long-Lived Assets [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 | | | |
Level 1 [Member] | Indefinite-lived Intangible Asset [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 | | | |
Level 1 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Level 1 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 7,200,000 | 7,200,000 | 11,100,000 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Level 2 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 40,400,000 | 40,400,000 | 318,800,000 | | |
Total Assets, Fair Value Disclosure | | 76,500,000 | 76,500,000 | 345,500,000 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Total Liabilities, Fair Value Disclosure | | (132,500,000) | (132,500,000) | (28,000,000) | | |
Level 2 [Member] | Long-Lived Assets [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 37,800,000 | 37,800,000 | | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | | | |
Level 2 [Member] | Indefinite-lived Intangible Asset [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 | | | |
Level 2 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 29,500,000 | 29,500,000 | 10,600,000 | | |
Derivative Liability, Fair Value | | (23,300,000) | (23,300,000) | (12,600,000) | | |
Level 2 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 6,600,000 | 6,600,000 | 16,100,000 | | |
Derivative Liability, Fair Value | | (109,200,000) | (109,200,000) | (15,400,000) | | |
Level 3 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 154,300,000 | 154,300,000 | 0 | | |
Total Assets, Fair Value Disclosure | | 154,300,000 | 154,300,000 | 0 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Total Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Level 3 [Member] | Long-Lived Assets [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 | | | |
Level 3 [Member] | Indefinite-lived Intangible Asset [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 154,300,000 | 154,300,000 | | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | | | |
Level 3 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Level 3 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Marketable Investments [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 10,900,000 | 10,900,000 | 326,000,000 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Marketable Investments [Member] | Level 1 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 8,300,000 | 8,300,000 | 7,200,000 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Marketable Investments [Member] | Level 2 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 2,600,000 | 2,600,000 | 318,800,000 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Marketable Investments [Member] | Level 3 [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Other Assets, Fair Value Disclosure | | 0 | 0 | 0 | | |
Other Liabilities, Fair Value Disclosure | | 0 | 0 | 0 | | |
Interest Rate Contract [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 4,000,000 | 4,000,000 | 700,000 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 4,000,000 | 4,000,000 | 700,000 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Interest Rate Contract [Member] | Level 1 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Interest Rate Contract [Member] | Level 2 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 4,000,000 | 4,000,000 | 700,000 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Interest Rate Contract [Member] | Level 3 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Foreign Exchange Contract [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 25,900,000 | 25,900,000 | 10,500,000 | | |
Derivative Liability, Fair Value | | (65,300,000) | (65,300,000) | (19,100,000) | | |
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 25,500,000 | 25,500,000 | 9,900,000 | | |
Derivative Liability, Fair Value | | (23,300,000) | (23,300,000) | (12,600,000) | | |
Foreign Exchange Contract [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 400,000 | 400,000 | 600,000 | | |
Derivative Liability, Fair Value | | (42,000,000) | (42,000,000) | (6,500,000) | | |
Foreign Exchange Contract [Member] | Level 1 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Foreign Exchange Contract [Member] | Level 1 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Foreign Exchange Contract [Member] | Level 2 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 25,500,000 | 25,500,000 | 9,900,000 | | |
Derivative Liability, Fair Value | | (23,300,000) | (23,300,000) | (12,600,000) | | |
Foreign Exchange Contract [Member] | Level 2 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 400,000 | 400,000 | 600,000 | | |
Derivative Liability, Fair Value | | (42,000,000) | (42,000,000) | (6,500,000) | | |
Foreign Exchange Contract [Member] | Level 3 [Member] | Designated as Hedging Instrument [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Foreign Exchange Contract [Member] | Level 3 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Commodity Contract [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 10,100,000 | 10,100,000 | 19,100,000 | | |
Derivative Liability, Fair Value | | (59,400,000) | (59,400,000) | (4,000,000) | | |
Commodity Contract [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 10,100,000 | 10,100,000 | 19,100,000 | | |
Derivative Liability, Fair Value | | (59,400,000) | (59,400,000) | (4,000,000) | | |
Commodity Contract [Member] | Level 1 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 7,200,000 | 7,200,000 | 11,100,000 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Commodity Contract [Member] | Level 2 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 2,900,000 | 2,900,000 | 8,000,000 | | |
Derivative Liability, Fair Value | | (59,400,000) | (59,400,000) | (4,000,000) | | |
Commodity Contract [Member] | Level 3 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Grain Contracts [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 3,300,000 | 3,300,000 | 7,500,000 | | |
Derivative Liability, Fair Value | | (7,800,000) | (7,800,000) | (4,900,000) | | |
Grain Contracts [Member] | Level 1 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | 0 | 0 | 0 | | |
Grain Contracts [Member] | Level 2 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 3,300,000 | 3,300,000 | 7,500,000 | | |
Derivative Liability, Fair Value | | (7,800,000) | (7,800,000) | (4,900,000) | | |
Grain Contracts [Member] | Level 3 [Member] | Not Designated as Hedging [Member] | | | | | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | | | | | |
Derivative Asset, Fair Value | | 0 | 0 | 0 | | |
Derivative Liability, Fair Value | | $ 0 | $ 0 | $ 0 | | |