Business Dispositions (Details 2) (Shipbuilding Segment, USD $)	12 Months Ended
	Dec. 31, 2011
Shipbuilding Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pro rata shares	6
Total shares distributed	48,800,000
Cash contribution from shipbuilding business spin-off	$ 1,400,000,000
Non-deductible transaction costs incurred from spin-off Shipbuilding business	$ 28,000,000