Fair Value (Details 2) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Fair Value of Long Term Debt [Line Items]
Long-Term Debt, Fair value	$ 8,800,000,000	$ 8,500,000,000.0
Long-Term Debt, Carrying value	$ 7,700,000,000	$ 8,000,000,000.0