v2.3.0.11
Pension and Other Postretirement Benefits (Components of the Plans' Net Periodic Benefits Cost) (Details) (USD $)
In Millions
3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Pension Benefits [Member]
       
Service cost $ 9.4 $ 9.8 $ 18.8 $ 19.5
Interest cost 29.9 31.4 59.8 62.8
Expected return on assets (41.8) (35.9) (83.6) (71.8)
Amortization of prior service cost 0.1 0.5 0.2 1.0
Recognized actuarial loss 13.9 14.5 27.8 29.0
Total Net Periodic Benefit Costs 11.5 20.3 23.0 40.5
Other Postretirement Benefits [Member]
       
Service cost 2.5 2.4 5.0 4.8
Interest cost 9.6 10.9 19.2 21.3
Expected return on assets (6.7) (5.8) (13.4) (11.7)
Amortization of transition obligation 0.3 0.3 0.6 0.6
Amortization of prior service cost (0.1) 0.8 (0.2) 0.7
Recognized actuarial loss 1.7 1.5 3.4 3.0
Total Net Periodic Benefit Costs $ 7.3 $ 10.1 $ 14.6 $ 18.7