Disposals and Discontinued Operations (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 acre	Dec. 31, 2011	Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal of Equity Interest In Segment Percentage	100.00%
Number of Acres Included in the Sale of the Segment	88,000
Proceeds from Divestiture of Businesses	$ 255	$ 0	$ 0
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	83
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	55
Allocation of Corporate Interest Costs	$ 0