Employee Retirement Plans and Postretirement Benefits Net Periodic Pension (Details) (Defined Benefit Plans and Other Postretirement Benefit, Cost [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 29, 2012		Dec. 31, 2011		Dec. 25, 2010
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	$ 19.7		$ 21.2		$ 19.9
Interest cost on projected benefit obligation	173.7		188.2		197.7
Expected return on plan assets	(175.2)		(199.4)		(179.9)
Amortization of prior service costs	(2.9)		(3.0)		(2.9)
Amortization of net actuarial loss	39.2		16.8		13.5
Curtailment loss	1.3	[1]	0	[1]	1.8	[1]
Special termination benefits	0.4	[1]	0	[1]	0	[1]
Defined Benefit Plan Expected Participant and National Insurance Contributions	(1.5)		(1.6)		(2.0)
Net periodic pension cost (benefit)	54.7		22.2		48.1
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	16.8		18.8		17.4
Interest cost on projected benefit obligation	165.7		180.5		188.3
Expected return on plan assets	(175.2)		(199.4)		(179.9)
Amortization of prior service costs	0.8		0.8		0.7
Amortization of net actuarial loss	39.4		20.2		13.6
Curtailment loss	1.3	[1]	0	[1]	1.8	[1]
Special termination benefits	0.4	[1]	0	[1]	0	[1]
Defined Benefit Plan Expected Participant and National Insurance Contributions	(1.5)		(1.6)		(2.0)
Net periodic pension cost (benefit)	47.7		19.3		39.9
OPEB
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	2.9		2.4		2.5
Interest cost on projected benefit obligation	8.0		7.7		9.4
Expected return on plan assets	0		0		0
Amortization of prior service costs	(3.7)		(3.8)		(3.6)
Amortization of net actuarial loss	(0.2)		(3.4)		(0.1)
Curtailment loss	0	[1]	0	[1]	0	[1]
Special termination benefits	0	[1]	0	[1]	0	[1]
Defined Benefit Plan Expected Participant and National Insurance Contributions	0		0		0
Net periodic pension cost (benefit)	$ 7.0		$ 2.9		$ 8.2

[1] We recognized a curtailment loss and special termination benefit charges during the fourth quarter of 2012 as a result of the restructuring program in Canada. See Note 9, "Special Items" for further discussion of the Canada restructuring program.