Retirement and Post Retirement Health Care Plans (Schedule Of Fair Value Of Plan Assets) (Details) - USD ($) $ in Millions	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 230.2	$ 203.4
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	11.2	113.1
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	8.3
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10.0	9.9	$ 10.3
Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	209.0	72.1
Net Asset Value | Common Collective Trust Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	209.0	72.1
Cash and Cash Equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.3	5.1
Cash and Cash Equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Cash and Cash Equivalents | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Common Stock | Level 1 | Domestic Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		26.4
Common Stock | Level 1 | International Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		19.2
Common Stock | Level 2 | Domestic Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Common Stock | Level 2 | International Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Common Stock | Level 3 | Domestic Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Common Stock | Level 3 | International Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Mutual Funds | Level 1 | US Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.6	30.1
Mutual Funds | Level 1 | International Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3.5	3.1
Mutual Funds | Level 1 | Balanced Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		9.5
Mutual Funds | Level 1 | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3.0	18.0
Mutual Funds | Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.8	1.7
Mutual Funds | Level 1 | Limited Liability Company
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Mutual Funds | Level 1 | Real Estate Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 2 | US Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 2 | International Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 2 | Balanced Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Mutual Funds | Level 2 | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 2 | Limited Liability Company
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		8.3
Mutual Funds | Level 2 | Real Estate Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 3 | US Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 3 | International Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 3 | Balanced Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Mutual Funds | Level 3 | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds | Level 3 | Limited Liability Company
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		0.0
Mutual Funds | Level 3 | Real Estate Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10.0	9.9
Estimate of Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	21.2	131.3
Estimate of Fair Value | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.3	5.1
Estimate of Fair Value | Common Stock | Domestic Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		26.4
Estimate of Fair Value | Common Stock | International Equities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		19.2
Estimate of Fair Value | Mutual Funds | US Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.6	30.1
Estimate of Fair Value | Mutual Funds | International Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3.5	3.1
Estimate of Fair Value | Mutual Funds | Balanced Funds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		9.5
Estimate of Fair Value | Mutual Funds | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3.0	18.0
Estimate of Fair Value | Mutual Funds | Other
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1.8	1.7
Estimate of Fair Value | Mutual Funds | Limited Liability Company
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets		8.3
Estimate of Fair Value | Mutual Funds | Real Estate Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 10.0	$ 9.9