Inventories, net (Tables)

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Inventories

Inventories, net consisted of the following (in millions):

	2017			2016
Work-in-process, primarily related to long-term contracts and programs in progress	$	6,510		$	7,864
Spare parts, used aircraft and general stock materials	811			833
Other inventories	1,134			719
Total inventories	8,455			9,416
Less: customer advances and progress payments	(3,968		)	(4,746		)
Total inventories, net	$	4,487		$	4,670