Summary of Significant Accounting Policies (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax Effects
Beginning Balance	$ (70,000,000)
Current period change	(41,000,000)
Ending Balance	(111,000,000)
Qualifying Hedges [Member]
Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax Effects
Beginning Balance	(35,000,000)
Current period change	(9,000,000)
Ending Balance	(44,000,000)
Marketable Securities [Member]
Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax Effects
Beginning Balance	7,000,000
Current period change	(4,000,000)
Ending Balance	3,000,000
Pension and Other Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax Effects
Beginning Balance	(42,000,000)
Current period change	(28,000,000)
Ending Balance	$ (70,000,000)