Retirement Plans (Postemployment Severance Plan And Defined Contribution Plan) (Narrative) (Details) - USD ($) shares in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 1996	May 26, 2019	May 27, 2018	May 28, 2017
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 (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		$ 947,900,000	$ 829,000,000.0
Defined contribution plan, expense recognized		26,100,000	19,600,000	$ 3,700,000
Amounts payable to highly compensated employees under non-qualified deferred compensation plan		237,900,000	227,900,000
ESOP borrowings from at variable interest rate	$ 16,900,000
ESOP's debt		700,000
Dividends received from employer		200,000	500,000	800,000
Contributions received from employer		$ 1,000,000.0	$ 100,000	$ 100,000
Common shares held in ESOP (shares)		1.9
ESOP, allocated shares (shares)		1.8
ESOP, suspense shares (shares)		0.1
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
Employee Stock Ownership Plan
Defined Benefit Plan Disclosure [Line Items]
Variable rate of interest (percentage)		2.48%
Maturity date of debt		Dec. 01, 2019