Accounts Receivable and Finance Receivables - Finance receivables by delinquency aging category (Details) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Finance receivables held for investment by delinquency aging
60 + days contractual delinquency as a percentage of finance receivables	4.97%	4.23%
Less than 31 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	$ 772	$ 857
31-60 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	31	49
61- 90 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	21	18
Over 90 days past due
Finance receivables held for investment by delinquency aging
Financing receivable held for investment	$ 21	$ 22