v2.4.0.6
Employee Benefits (Narrative) (Details) (USD $)
In Billions, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Defined Benefit Plan Disclosure [Line Items]  
Amount paid in severance benefits over the period $ 0.1
Postemployment benefits liability 1
Qualified Pension Trusts [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Defined benefit plan contributions by employer 0.4
Nonqualified Pension Plans [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Defined benefit plan contributions by employer 0.1
Other Postretirement Benefit Plans [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Defined benefit plan contributions by employer $ 0.4