Financial Instruments, Risk Management Activities, and Fair Values (Schedule of interest rate hedge in AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 26, 2019
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (35.7)
3.15% notes due December 15, 2021 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (15.2)
Derivative, Maturity Date	Dec. 15, 2021
Debt Instrument, Interest Rate, Stated Percentage	3.15%	3.15%
2.6% notes due October 12, 2022 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ 1.7
Derivative, Maturity Date	Oct. 12, 2022
Debt Instrument, Interest Rate, Stated Percentage	2.60%	2.60%
1.0% notes due April 27, 2023 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (0.7)
Derivative, Maturity Date	Apr. 27, 2023
Debt Instrument, Interest Rate, Stated Percentage	1.00%	1.00%
3.7% notes due October 17, 2023 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (1.1)
Derivative, Maturity Date	Oct. 17, 2023
Debt Instrument, Interest Rate, Stated Percentage	3.70%	3.70%
3.65% notes due February 15, 2024 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ 6.6
Derivative, Maturity Date	Feb. 15, 2024
Debt Instrument, Interest Rate, Stated Percentage	3.65%	3.65%
4.0% notes due April 17, 2025 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (2.8)
Derivative, Maturity Date	Apr. 17, 2025
Debt Instrument, Interest Rate, Stated Percentage	4.00%	4.00%
3.2% notes due February 10, 2027 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ 11.4
Derivative, Maturity Date	Feb. 10, 2027
Debt Instrument, Interest Rate, Stated Percentage	3.20%	3.20%
1.5% notes due April 27, 2027 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (2.3)
Derivative, Maturity Date	Apr. 27, 2027
Debt Instrument, Interest Rate, Stated Percentage	1.50%	1.50%
4.2% notes due April 17, 2028 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (8.0)
Derivative, Maturity Date	Apr. 17, 2028
Debt Instrument, Interest Rate, Stated Percentage	4.20%	4.20%
4.55% notes due April 17, 2038 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (9.8)
Derivative, Maturity Date	Apr. 17, 2038
Debt Instrument, Interest Rate, Stated Percentage	4.55%	4.55%
5.4% notes due June 15, 2040 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (11.2)
Derivative, Maturity Date	Jun. 15, 2040
Debt Instrument, Interest Rate, Stated Percentage	5.40%	5.40%
4.15% notes due February 15, 2043 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ 8.9
Derivative, Maturity Date	Feb. 15, 2043
Debt Instrument, Interest Rate, Stated Percentage	4.15%	4.15%
4.7% notes due April 17, 2048 [Member]
Debt Instrument [Line Items]
Pre-tax hedge gain (loss) in AOCI	$ (13.2)
Derivative, Maturity Date	Apr. 17, 2048
Debt Instrument, Interest Rate, Stated Percentage	4.70%	4.70%