Annual report pursuant to Section 13 and 15(d)

Benefit Costs Included in Accumulated Other Comprehensive Loss that have not yet Recognized in Net Periodic Pension Cost (Parenthetical) (Detail)

v2.4.0.6
Benefit Costs Included in Accumulated Other Comprehensive Loss that have not yet Recognized in Net Periodic Pension Cost (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]      
Accumulated other comprehensive loss $ 276.4 $ 300.3 $ 241.3
Pension Benefits
     
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost, accumulated taxes 3.5 0.9  
Net Actuarial Loss, Accumulated Taxes 151.5 165.6  
Accumulated other comprehensive loss 268.9 290.4  
Other Benefits
     
Defined Benefit Plan Disclosure [Line Items]      
Prior service cost, accumulated taxes (0.3) (0.4)  
Net Actuarial Loss, Accumulated Taxes 4.6 6.0  
Accumulated other comprehensive loss $ 7.5 $ 9.9