XML 127 R64.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value (Details 2) (USD $)
In Billions, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Fair Value of Long Term Debt [Line Items]    
Long-Term Debt, Fair value $ 8.8 $ 8.5
Long-Term Debt, Carrying value $ 7.7 $ 8.0