Accounts Receivable and Contract Assets (Tables)

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Accounts receivable, net

Accounts receivable were comprised of the following:

	December 31
($ in millions)	2018			2017
Due from U.S. Government	$	216		$	275
Due from other customers	45			167
Total accounts receivable	261			442
Allowances for doubtful accounts	(9		)	(13		)
Total accounts receivable, net	$	252		$	429

Contract assets

Contract assets were comprised of the following:

	December 31
($ in millions)	2018		2017
Due from U.S. Government	$	899	$	733
Due from other customers	104		26
Total contract assets	1,003		759