Other Postretirement Employee Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) - Other Postretirement Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.7	$ 1.1
Interest cost	6.6	8.4
Amortization of net loss	0.0	1.0
Amortization of prior service credit	(3.1)	(3.1)
Net periodic pension cost	$ 4.2	$ 7.4