v2.4.0.6
Retirement Plans (Schedule Of Changes In Level 3 Assets) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]      
Level 3 plan assets $ 90 $ 58 $ 51
Investment Returns Of Hedge Funds [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Level 3 plan assets (1) 4  
Purchases Of Hedge Funds [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Level 3 plan assets $ 33 $ 3