Receivables (Details) (USD $)	3 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	$ 560,944,000	$ 499,222,000
Period of performance criteria (in years)	15
Potential refund if performance criteria are not met	19,700,000
Percentage of Commercial Resupply Svcs Contract Launch Delivery	25.00%
Revenue from Commercial Resupply Svcs contract inception to date	1,100,000,000
Contract value of Commercial Resupply Svcs contract	1,900,000,000
Billed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	48,294,000	59,496,000
Unbilled [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	512,650,000	439,726,000
Incentive fees due incrementally	8,300,000	8,700,000
Period of incentive fees due (in years)	15
Receivables pertaining to the commercial resupply services contract	$ 343,000,000	$ 277,000,000