Supplemental Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 27, 2012	May 29, 2011	May 30, 2010	May 31, 2009
Receivables [Abstract]
From customers	$ 1,345.3	$ 1,178.6
Less allowance for doubtful accounts	(21.7)	(16.3)
Total	1,323.6	1,162.3
Inventory, Net [Abstract]
Raw materials and packaging	334.4	286.2
Finished goods	1,211.8	1,273.6
Grain	155.3	218.0
Excess of FIFO over LIFO cost (a)	(222.7)	(168.5)
Total	1,478.8	1,609.3
LIFO Inventory Amount	930.2	1,034.1
Prepaid Expenses And Other Assets Current [Abstract]
Prepaid expenses	178.3	161.0
Accrued interest receivable, including interest rate swaps	15.0	29.0
Derivative receivables, primarily commodity-related	34.5	109.1
Other receivables	103.8	104.7
Grain Derivative Asset Not Designated As Hedging Instrument Fair Value Current	8.3	57.3
Miscellaneous	18.2	22.4
Total	358.1	483.5
Property, Plant and Equipment, Net [Abstract]
Land	75.9	61.2
Buildings	1,980.6	1,777.7
Buildings under capital lease	0.3	25.0
Equipment	5,257.2	4,719.7
Equipment under capital lease	9.0	18.9
Capitalized Software	419.1	367.7
Construction in progress	542.6	521.9
Total land, buildings, and equipment	8,284.7	7,492.1
Less accumulated depreciation	(4,632.0)	(4,146.2)
Total	3,652.7	3,345.9
Other Assets, Noncurrent [Abstract]
Pension assets	42.7	128.6
Investments in and advances to joint ventures	529.0	519.1
Life insurance	86.7	87.2
Non-current derivative receivables	6.2	13.3
Exchangeable Note	98.9	0
Miscellaneous	101.8	114.3
Total	865.3	862.5
Other Liabilities, Current [Abstract]
Accrued payroll	367.4	303.3
Accrued interest	100.2	114.0
Accrued trade and consumer promotions	560.7	463.0
Accrued taxes	39.2	80.4
Derivatives payable	26.1	34.8
Accrued customer advances	4.6	36.4
Restructuring Reserve	85.9	7.2	10.8	18.8
Grain Derivative Liability Not Designated As Hedging Instrument Fair Value Current	20.6	28.7
Miscellaneous	221.9	253.7
Total	1,426.6	1,321.5
Other Liabilities, Noncurrent [Abstract]
Interest rate swaps	8.9	22.2
Accrued compensation and benefits, including obligations for underfunded other postretirement and postemployment benefit plans	1,853.1	1,412.8
Accrued income taxes	230.9	233.3
Miscellaneous	96.9	64.9
Total	2,189.8	1,733.2
Earnings Supplemental [Abstract]
Depreciation and amortization	541.5	472.6	457.1
Research and development expense	245.4	235.0	218.3
Advertising and media expense (including production and communication costs)	913.7	843.7	908.5
Interest Income (Expense), Net [Abstract]
Interest expense	370.7	360.9	374.5
Capitalized interest	(8.9)	(7.2)	(6.2)
Interest income	(9.9)	(7.4)	(6.8)
Loss on debt repurchase	0	0	40.1
Total	351.9	346.3	401.6
Supplemental Cash Flow Information [Abstract]
Cash interest payments	344.3	333.1	384.1
Cash paid for income taxes	$ 590.6	$ 699.3	$ 672.5