Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2012

Receivables [Abstract]

Accounts receivable

Accounts receivable consisted of the following:

	December 31
$ in millions	2012			2011
Due on U.S. Government contracts
Amounts billed		$ 794			$ 812
Recoverable costs and accrued profit on progress completed - unbilled	1,396			1,594
	2,190			2,406
Due on non-U.S. Government contracts
Amounts billed	314			249
Recoverable costs and accrued profit on progress completed - unbilled	414			363
	728			612
Total accounts receivable	2,918			3,018
Allowance for doubtful accounts	(60		)	(54		)
Total accounts receivable, net		$2,858			$2,964