Segment Disclosures - Summary of Revenue From Services by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from services	$ 1,422.3	$ 1,328.8	$ 1,333.6	$ 1,289.7	$ 1,304.4	$ 1,247.8	$ 1,375.5	$ 1,349.1	$ 5,374.4	$ 5,276.8	$ 5,518.2	[1]
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from services									3,894.6	3,722.5	3,705.2
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from services									$ 1,479.8	$ 1,554.3	$ 1,813.0

[1] Fiscal year included 53 weeks.