6. Receivables


	December 31,
($ in millions)	2016		2015

Trade accounts receivable	$	1,169	$	759
Less allowance for doubtful accounts		(11)		(5)
Net trade accounts receivable		1,158		754
Other receivables		333		131
	$	1,491	$	885

Net accounts receivable under long-term contracts, due primarily from agencies of the U.S. government and their prime contractors, were $224 million and $196 million for the years ended December 31, 2016 and 2015, respectively, and included $165 million and $145 million at each period end, respectively, representing the recognized sales value of performance that was not yet billable to customers. The average length of the long-term contracts is approximately 2.5 years, and the average length remaining on those contracts at December 31, 2016, was one year. At December 31, 2016, $223 million of net accounts receivables is expected to be collected within the next year and is related to customary fees and cost withholdings that will be paid upon milestone or contract completions, as well as final overhead rate settlements.

Other receivables include income and sales tax receivables, certain vendor rebate receivables and other miscellaneous receivables.

The company has entered into several regional uncommitted and committed accounts receivable factoring programs with various financial institutions for certain receivables of the company. Programs accounted for as true sales of the receivables, without recourse to Ball, had combined limits of approximately $970 million at December 31, 2016. A total of $596 million and $479 million were sold under these programs as of December 31, 2016 and 2015, respectively. Additionally, the company has programs that were not accounted for as true sales of the receivables, with combined limits of $30 million, under which $17 million was outstanding at December 31, 2016, and was reflected as short-term debt.