Accounts Receivable Net (Tables)

12 Months Ended

Dec. 31, 2010

Accounts Receivable Net (Table) [Abstract]

Accounts receivable

	December 31
$ in millions	2010			2009
Due From U.S. Government
Amounts billed	$	900		$	837
Recoverable costs and accrued profit on progress completed – unbilled		1,718			1,414
		2,618			2,251
Due From Other Customers
Amounts billed		280			308
Recoverable costs and accrued profit on progress completed – unbilled		458			341
		738			649
Total accounts receivable		3,356			2,900
Allowance for doubtful accounts		(27	)		(41	)
Total accounts receivable, net	$	3,329		$	2,859