Inventories

Inventories at December 31 consisted of the following:



	2017			2016
Long-term contracts in progress		$13,889			$12,801
Commercial aircraft programs	52,861			52,048
Commercial spare parts, used aircraft, general stock materials and other	5,688			5,446
Inventory before advances and progress billings	72,438			70,295
Less advances and progress billings	(28,094		)	(27,096		)
Total		$44,344			$43,199

Long-Term Contracts in Progress

Long-term contracts in progress includes Delta launch program inventory that is being sold at cost to United Launch Alliance (ULA) under an inventory supply agreement that terminates on March 31, 2021. The inventory balance was $120 (net of advances of $164 and $220) at December 31, 2017 and 2016. See indemnifications to ULA in Note 12.

Included in inventories at December 31, 2017 and 2016 are capitalized precontract costs of $933 and $729 primarily related to KC-46A Tanker, C-17 and F/A-18. See Note 11.

Commercial Aircraft Programs

At December 31, 2017 and 2016, commercial aircraft programs inventory included the following amounts related to the 787 program: $30,695 and $32,501 of work in process (including deferred production costs of $25,358 and $27,308), $3,189 and $2,398 of supplier advances, and $3,173 and $3,625 of unamortized tooling and other non-recurring costs. At December 31, 2017, $22,220 of 787 deferred production costs, unamortized tooling and other non-recurring costs are expected to be recovered from units included in the program accounting quantity that have firm orders and $6,311 is expected to be recovered from units included in the program accounting quantity that represent expected future orders.

At December 31, 2017 and 2016, commercial aircraft programs inventory included $151 and $284 of unamortized tooling costs related to the 747 program. At December 31, 2017, $146 of 747 unamortized tooling costs are expected to be recovered from units included in the program accounting quantity that have firm orders or commitments. The program accounting quantity includes one already completed aircraft which is being remarketed.

Commercial aircraft programs inventory included amounts credited in cash or other consideration (early issue sales consideration) to airline customers totaling $2,976 and $3,117 at December 31, 2017 and 2016.