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Employee Benefit Plans (Net Pension And Postretirement Cost) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Pension Plan [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 4.9 $ 4.2
Interest cost 5.1 5.0
Expected return on plan assets (9.4) (8.7)
Amortization of net actuarial losses 3.1 3.0
Amortization of prior service cost 0.3 0.3
Net periodic pension or postretirement benefit cost 4.0 3.8
Postretirement Benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Interest cost 0.4 0.4
Amortization of prior service cost 0.1 0.1
Net periodic pension or postretirement benefit cost $ 0.5 $ 0.5