Retirement and Other Employee Benefits (Fair Values of Plan Assets by Asset Category) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 26, 2014		Dec. 27, 2013		Dec. 28, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 14.1		$ 14.2
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.7		3.5
Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.3		1.0
Value Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.1		5.6
Growth Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.0		4.1
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	14.1		14.2
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.7		3.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.3		1.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Value Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.1		5.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Growth Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.0		4.1
Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Observable Inputs (Level 2) [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Observable Inputs (Level 2) [Member] | Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Observable Inputs (Level 2) [Member] | Value Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Observable Inputs (Level 2) [Member] | Growth Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Value Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
Significant Unobservable Inputs (Level 3) [Member] | Growth Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED STATES Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	14.1	[1]	14.2	[1]	13.5	[1]
UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	55.4		54.9
UNITED KINGDOM [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.1		0.7
UNITED KINGDOM [Member] | United Kingdom Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	23.1		23.1
UNITED KINGDOM [Member] | United States Companies [Membeer]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets			7.6
UNITED KINGDOM [Member] | Other International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	20.5		12.5
UNITED KINGDOM [Member] | United Kingdom Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.0		4.8
UNITED KINGDOM [Member] | United Kingdom Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	6.7		6.2
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	55.4		54.9
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.1		0.7
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | United Kingdom Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	23.1		23.1
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | United States Companies [Membeer]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets			7.6
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	20.5		12.5
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | United Kingdom Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.0		4.8
UNITED KINGDOM [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | United Kingdom Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	6.7		6.2
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | United Kingdom Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | United States Companies [Membeer]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets			0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | Other International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | United Kingdom Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Observable Inputs (Level 2) [Member] | United Kingdom Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | United Kingdom Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | United States Companies [Membeer]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets			0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | United Kingdom Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Significant Unobservable Inputs (Level 3) [Member] | United Kingdom Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0		0
UNITED KINGDOM [Member] | Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 55.4	[1]	$ 54.9	[1]	$ 45.6	[1]

[1] The accumulated benefit obligation is the same as the projected benefit obligation.