Retirement Plans (Defined Contribution Plan) (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 1996	May 31, 2020	May 26, 2019	May 27, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, required minimum age (in years)		21 years
Defined benefit plan, minimum period to perform service requirement (in years)		1 year
Percentage of employer contribution (percentage)		6.00%
Defined contribution plan, annual contributions per employee, percent		1.50%
Defined benefit plan net assets		$ 870,200,000	$ 947,900,000
Defined contribution plan, expense recognized		19,900,000	26,100,000	$ 19,600,000
Amounts payable to highly compensated employees under non-qualified deferred compensation plan		242,500,000	237,900,000
ESOP borrowings from at variable interest rate	$ 16,900,000
Dividends received from employer		200,000	200,000	500,000
Contributions received from employer		500,000	$ 1,000,000.0	$ 100,000
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution (per dollar)		0.25
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution (per dollar)		$ 1.20