LONG-TERM DEBT (Schedule of Debt) (Details) - USD ($) $ in Millions	May 29, 2016	May 31, 2015
Debt Instrument [Line Items]
Total face value of debt	$ 5,477.2	$ 7,801.0
Unamortized fair value adjustment of senior debt in connection with Ralcorp	39.8	146.7
Unamortized discounts/premiums	(19.8)	(32.8)
Unamortized debt issuance costs	(14.6)	(30.1)
Adjustment due to hedging activity	6.6	11.8
Less current installments	(571.4)	(1,007.8)
Total long-term debt	4,917.8	6,888.8
4.65% senior debt due January 2043
Debt Instrument [Line Items]
Total face value of debt	$ 176.7	$ 737.0
Interest rate	4.65%	4.65%
6.625% senior debt due August 2039
Debt Instrument [Line Items]
Total face value of debt	$ 91.4	$ 450.0
Interest rate	6.625%	6.625%
8.25% senior debt due September 2030
Debt Instrument [Line Items]
Total face value of debt	$ 300.0	$ 300.0
Interest rate	8.25%	8.25%
7.0% senior debt due October 2028
Debt Instrument [Line Items]
Total face value of debt	$ 382.2	$ 382.2
Interest rate	7.00%	7.00%
6.7% senior debt due August 2027
Debt Instrument [Line Items]
Total face value of debt	$ 9.2	$ 9.2
Interest rate	6.70%	6.70%
7.125% senior debt due October 2026
Debt Instrument [Line Items]
Total face value of debt	$ 262.5	$ 372.4
Interest rate	7.125%	7.125%
3.2% senior debt due January 2023
Debt Instrument [Line Items]
Total face value of debt	$ 837.0	$ 1,000.0
Interest rate	3.20%	3.20%
3.25% senior debt due September 2022
Debt Instrument [Line Items]
Total face value of debt	$ 250.0	$ 250.0
Interest rate	3.25%	3.25%
9.75% subordinated debt due March 2021
Debt Instrument [Line Items]
Total face value of debt	$ 195.9	$ 195.9
Interest rate	9.75%	9.75%
4.95% senior debt due August 2020
Debt Instrument [Line Items]
Total face value of debt	$ 197.7	$ 300.0
Interest rate	4.95%	4.95%
7.0% senior debt due April 2019
Debt Instrument [Line Items]
Total face value of debt	$ 335.0	$ 475.0
Interest rate	7.00%	7.00%
2.1% senior debt due March 2018
Debt Instrument [Line Items]
Total face value of debt	$ 225.0	$ 225.0
Interest rate	2.10%	2.10%
1.9% senior debt due January 2018
Debt Instrument [Line Items]
Total face value of debt	$ 1,000.0	$ 1,000.0
Interest rate	1.90%	1.90%
5.819% senior debt due June 2017
Debt Instrument [Line Items]
Total face value of debt	$ 475.0	$ 475.0
Interest rate	5.819%	5.819%
LIBOR plus 0.37% senior notes due July 2016
Debt Instrument [Line Items]
Total face value of debt	$ 550.0	$ 550.0
Interest rate	0.37%	0.37%
1.3% senior debt due January 2016
Debt Instrument [Line Items]
Total face value of debt	$ 0.0	$ 750.0
Interest rate	1.30%	1.30%
1.35% senior debt due September 2015
Debt Instrument [Line Items]
Total face value of debt	$ 0.0	$ 250.0
Interest rate	1.35%	1.35%
2.00% to 9.59% lease financing obligations due on various dates through 2040
Debt Instrument [Line Items]
Total face value of debt	$ 149.2	$ 68.4
2.00% to 9.59% lease financing obligations due on various dates through 2040 | Minimum
Debt Instrument [Line Items]
Interest rate	2.00%	2.00%
2.00% to 9.59% lease financing obligations due on various dates through 2040 | Maximum
Debt Instrument [Line Items]
Interest rate	9.59%	9.59%
Other indebtedness
Debt Instrument [Line Items]
Total face value of debt	$ 40.4	$ 10.9