XML 70 R59.htm IDEA: XBRL DOCUMENT v3.5.0.2
Defined Benefit Plans - Components of Net Periodic Benefit Cost for Pension and Postretirement Benefits (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Mar. 31, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]          
Recognition of actuarial losses (gains)     $ 2.8 $ 1.9 $ 8.9
Pension Benefits [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Service cost $ 1.6   2.3 7.2 8.7
Interest cost 8.4   8.3 25.8 25.2
Expected return on plan assets (8.9)   (9.9) (27.9) (30.3)
Recognition of prior service costs (credits)     0.1   0.1
Recognition of actuarial losses (gains)     2.9   2.9
Net periodic benefit cost (income) 1.1   3.7 5.1 6.6
Postretirement Benefits [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Interest cost (0.1)   0.1 0.2 0.4
Recognition of prior service costs (credits) (3.8)   (3.3) (10.0) (10.3)
Recognition of actuarial losses (gains) 1.0 $ 0.9 (0.1) 1.9 (0.1)
Net periodic benefit cost (income) $ (2.9)   $ (3.3) $ (7.9) $ (10.0)