Segment Disclosures - Segment Revenue Per Service (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 03, 2016	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Jan. 03, 2016		Dec. 28, 2014	Dec. 29, 2013
Revenue from Services:
Segment revenue for service	$ 1,461.6	$ 1,351.0	$ 1,385.0	$ 1,320.6	$ 1,425.0	$ 1,396.4	$ 1,410.5	$ 1,330.8	$ 5,518.2	[1]	$ 5,562.7	$ 5,413.1
Reporting Segments | Total Americas Commercial and PT
Revenue from Services:
Segment revenue for service									3,576.2		3,565.6	3,513.4
Reporting Segments | Total EMEA Commercial and PT
Revenue from Services:
Segment revenue for service									945.0		1,085.0	1,057.2
Reporting Segments | Total APAC Commercial and PT
Revenue from Services:
Segment revenue for service									387.7		392.2	382.7
Reporting Segments | Americas Commercial
Revenue from Services:
Segment revenue for service									2,604.3		2,609.6	2,545.6
Reporting Segments | Americas PT
Revenue from Services:
Segment revenue for service									971.9		956.0	967.8
Reporting Segments | EMEA Commercial
Revenue from Services:
Segment revenue for service									773.5		894.7	877.5
Reporting Segments | EMEA PT
Revenue from Services:
Segment revenue for service									171.5		190.3	179.7
Reporting Segments | APAC Commercial
Revenue from Services:
Segment revenue for service									347.2		351.8	344.1
Reporting Segments | APAC PT
Revenue from Services:
Segment revenue for service									40.5		40.4	38.6
Reporting Segments | OCG
Revenue from Services:
Segment revenue for service									673.8		586.8	509.5
Less: Intersegment revenue
Revenue from Services:
Segment revenue for service									$ (64.5)		$ (66.9)	$ (49.7)

[1] Fiscal year included 53 weeks.