Quarterly report pursuant to Section 13 or 15(d)

Pensions and Other Postretirement Benefits (Components of OPEB Expense) (Details)

 v2.3.0.11
Pensions and Other Postretirement Benefits (Components of OPEB Expense) (Details) (Other Benefits [Member], USD $)
In Millions
3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Other Benefits [Member]
       
Service cost $ 2.3 $ 1.6 $ 4.7 $ 3.2
Interest cost 5.3 5.5 11.2 10.7
Expected return on plan assets (3.7) (3.3) (8.0) (6.5)
Prior service costs 0.2 0.5 0.8 0.9
Net actuarial loss 2.9 1.7 5.8 3.4
Net periodic benefit cost 7.0 6.0 14.5 11.7
Quarterly OPEB contributions     $ 21.9 $ 17.4