Pensions and Postretirement Benefits Other Than Pensions (Schedule of Pretax Amounts Recognized in Accumulated Other Comprehensive Income (Loss) Other Than Pension) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Postretirement [Member]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	$ 2.9	$ (0.5)
Balance at December 31, 2011	2.7	4.8
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(1.6)	(1.6)
Balance at December 31, 2012	4.0	2.7
Net Actuarial Losses [Member]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	2.9	(0.5)
Balance at December 31, 2011	(1.2)	(0.7)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.0	0.0
Balance at December 31, 2012	1.7	(1.2)
prior service gains [Member]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	0.0	0.0
Balance at December 31, 2011	3.9	5.5
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(1.6)	(1.6)
Balance at December 31, 2012	$ 2.3	$ 3.9