Accounts Receivable and Finance Receivables - Finance receivables by delinquency aging category (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jan. 02, 2016
Finance receivables held for investment by delinquency aging
60+ days contractual delinquency as a percentage of finance receivables	4.23%	6.24%
Less than 31 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	$ 857	$ 950
31-60 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	49	86
61- 90 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	18	42
Over 90 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	$ 22	$ 27