Pension Plans and Postretirement Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension expense	$ 1.7	$ 16.6	$ 6.6
Amount recoverable from government contract due to US government cost accounting standards	13.8	14.5	12.7
Pretax contribution		83.0
Employer contributions to 401(k) plans	9.5	9.1	8.2
Non-cash reduction to stockholders' equity	227.3	129.8
Deferred tax on non-cash reductions to stockholders' equity	135.0	78.8
Assumed rate of increase in the per capita cost of covered benefits	6.50%
Ultimate health care cost trend rate, 2018 and thereafter	5.00%
Effect of one percentage point increase in assumed health care cost trend rates on annual service and interest costs (increase of less than $0.1 million)	0.1
Effect of one percentage point increase in assumed health care cost trend rates on postretirement benefit obligation	0.5
Effect of one percentage point decrease in assumed health care cost trend rates on annual service and interest costs (decrease of less than $0.1 million)	0.1
Effect of one percentage point decrease in assumed health care cost trend rates on postretirement benefit obligation	0.4
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost expected to be recognized for the pension plans, net gain (loss)	(32.2)
Net periodic benefit cost expected to be recognized for the pension plans, net prior service credit	4.2
Fair value of plan assets	1,005.1	1,038.4
Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Percentage of employees under defined benefit pension plan	18.00%
Assumed discount rate on plan liabilities	4.50%	5.40%	4.40%
Projected long-term rate of return on plan assets		8.25%
Net periodic pension expense	(1.7)	16.6	6.6
Pretax contribution	0	83.0
Settlements	32.4		32.8
Fair value of plan assets	957.5	986.3	793.3
Expected weighted-average long-term rate of return	8.25%	8.25%	8.25%
Weighted average increase in future compensation levels	2.75%	2.75%	2.75%
Unrecognized net (gain) loss	(379.6)	(243.5)
Unrecognized prior service credit	(27.0)	(33.1)
Pension Benefits Foreign Plans
Defined Benefit Plan Disclosure [Line Items]
Number of employees covered	520
Net periodic pension expense	0.4	0.9	0.4
Pretax contribution	0	0
Fair value of plan assets	47.6	52.1	42.3
Weighted average increase in future compensation levels			1.75%
Unrecognized net (gain) loss	(12.9)	(3.7)
Unrecognized prior service credit	(0.1)	(0.1)
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension expense	(0.1)	(0.2)	(0.1)
Net periodic benefit cost expected to be recognized for the pension plans, net gain (loss)	0.2
Net periodic benefit cost expected to be recognized for the pension plans, net prior service credit	0.1
Unrecognized net (gain) loss	3.1	5.2
Unrecognized prior service credit	0.1	(0.2)
Equity instruments | Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets	70.00%
Target allocation of plan assets, minimum	45.00%
Target allocation of plan assets, maximum	75.00%
Equity instruments | Pension Benefits Foreign Plans
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets	60.00%
Fixed income instruments | Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets	30.00%
Debt Securities and Other | Pension Benefits Foreign Plans
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets	40.00%
Fair Value, Inputs, Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	464.6	535.2
Fair Value, Inputs, Level 1 | Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	464.6
Fair Value, Inputs, Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	536.7	498.9
Fair Value, Inputs, Level 2 | Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	536.7
Fair Value, Inputs, Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.8	4.3
Fair Value, Inputs, Level 3 | Pension Benefits Domestic Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 3.8