Long Term Debt (Details 1) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
Debt Retirements and Redemptions
Extinguishment of debt	$ 626
Income Tax Revenue Bonds [Member]
Debt Retirements and Redemptions
Interest rate on debt portion expected to be repaid	6.95%
Extinguishment of debt	26
Senior Notes [Member]
Debt Retirements and Redemptions
Interest rate on debt portion expected to be repaid	7.05%
Extinguishment of debt	$ 600