Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2013

Receivables [Abstract]

Accounts receivable

Accounts receivable consisted of the following:

	December 31
$ in millions	2013			2012
Due from U.S. Government
Billed		$ 596			$ 783
Unbilled	5,801			5,284
Progress and performance-based payments received	(4,385		)	(3,907		)
	2,012			2,160
Due from Other Customers (inclusive of foreign military sales)
Billed	296			325
Unbilled	2,830			1,992
Progress and performance-based payments received	(2,384		)	(1,559		)
	742			758
Total accounts receivable	2,754			2,918
Allowance for doubtful accounts	(69		)	(60		)
Total accounts receivable, net		$2,685			$2,858