Segment Disclosures - Segment Revenue Per Service (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Revenue from Services
Segment Revenue from Services	$ 1,385.0	$ 1,410.5	$ 2,705.6	$ 2,741.3
Less: Intersegment revenue
Revenue from Services
Segment Revenue from Services	(16.7)	(15.9)	(34.5)	(30.3)
Total Americas Commercial and PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	897.5	905.3	1,771.7	1,754.9
Total EMEA Commercial and PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	238.6	286.7	457.2	556.3
Total APAC Commercial and PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	100.6	96.5	196.7	188.1
Americas Commercial | Reporting Segments
Revenue from Services
Segment Revenue from Services	651.3	661.1	1,292.7	1,274.3
Americas PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	246.2	244.2	479.0	480.6
EMEA Commercial | Reporting Segments
Revenue from Services
Segment Revenue from Services	195.7	237.0	374.0	458.9
EMEA PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	42.9	49.7	83.2	97.4
APAC Commercial | Reporting Segments
Revenue from Services
Segment Revenue from Services	90.3	86.5	175.9	169.5
APAC PT | Reporting Segments
Revenue from Services
Segment Revenue from Services	10.3	10.0	20.8	18.6
OCG | Reporting Segments
Revenue from Services
Segment Revenue from Services	$ 165.0	$ 137.9	$ 314.5	$ 272.3