INVESTMENTS IN JOINT VENTURES - Summary of Combined Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	May 30, 2021	May 31, 2020	May 26, 2019
Statement of Earnings
Total earnings after income taxes	$ 1,300.9	$ 841.8	$ 678.4
Balance Sheet
Current assets	2,702.1	2,885.9
Current liabilities	3,306.2	3,287.4
Ardent Mills
Balance Sheet
Current assets	1,101.5	1,010.6
Noncurrent assets	1,848.2	1,720.2
Current liabilities	524.1	454.8
Noncurrent liabilities	563.0	503.4
Other
Balance Sheet
Current assets	95.0	87.1
Noncurrent assets	36.8	24.5
Current liabilities	39.9	44.1
Noncurrent liabilities	10.6	8.3
Equity Method Investments
Statement of Earnings
Total net sales	3,646.4	3,618.9	3,671.4
Total gross margin	407.9	362.5	327.4
Total earnings after income taxes	189.1	163.8	170.0
Equity Method Investments | Ardent Mills
Statement of Earnings
Total net sales	3,407.6	3,393.9	3,476.0
Total gross margin	360.6	313.1	281.9
Total earnings after income taxes	169.6	144.5	151.9
Equity Method Investments | Other
Statement of Earnings
Total net sales	238.8	225.0	195.4
Total gross margin	47.3	49.4	45.5
Total earnings after income taxes	$ 19.5	$ 19.3	$ 18.1