Supplemental Financial Statement Data Allowance for doubtful accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Supplemental Financial Statement Data [Abstract]
Balance at beginning of year	$ 8	$ 7	$ 5
Additions charged to expense	9	4	6
Doubtful accounts charged to reserve	(9)	(3)	(4)
Balance at end of year	$ 8	$ 8	$ 7