Employee Benefits (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Employer Contribution	$ 6.5
Defined Benefit Plan, Expected Contributions in Current Fiscal Year	10.0
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Employer Contribution	0.2
Defined Benefit Plan, Expected Contributions in Current Fiscal Year	$ 2.4