Receivables (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Receivables [Abstract]
Trade receivables	$ 2,078	$ 2,368
Costs and estimated earnings in excess of billings on uncompleted contracts	397	253
Other receivables	134	119
Allowance for doubtful accounts	(29)	(21)
Total receivables	$ 2,580	$ 2,719