Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Amortization of Net Loss [Member]
Amounts recognized as a component of net periodic pension and other postretirement benefit cost:
Total before income taxes	$ (5.8)	$ (6.5)	$ (16.0)	$ (19.1)
Amortization of Prior Service Credit [Member]
Amounts recognized as a component of net periodic pension and other postretirement benefit cost:
Total before income taxes	4.3	1.2	6.8	3.4
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Amounts recognized as a component of net periodic pension and other postretirement benefit cost:
Total before income taxes	(1.5)	(5.3)	(9.2)	(15.7)
Income tax benefit	0.5	1.9	3.2	5.5
Total reclassifications for the period, net of income taxes	$ (1.0)	$ (3.4)	$ (6.0)	$ (10.2)