Restructuring Expenses (Details) - IS&GS Acquisition - USD ($) $ in Millions	12 Months Ended
	Jan. 03, 2020	Dec. 28, 2018	Dec. 29, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 1	$ 8	$ 37
Restructuring expenses incurred to date	58
Severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0	2	18
Lease termination expenses
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 1	$ 6	$ 19