Employee Benefit Plans (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 8.8
Estimated minimum contributions	28.1
Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	0.6
Estimated minimum contributions	$ 1.5