Employee Benefit Plans (Amounts Recognized in AOCI and Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes recognized in other comprehensive income (loss):
Total recognized in other comprehensive income	$ (7.3)	$ (6.3)	$ (9.7)
Pension Benefits [Member]
Amounts recognized in other comprehensive income (loss):
Prior service costs	(0.8)	(0.9)
Actuarial loss	(194.6)	(197.3)
Subtotal	(195.4)	(198.2)
Deferred taxes	71.2	71.0
Net amount recognized	(124.2)	(127.2)
Changes recognized in other comprehensive income (loss):
Current year prior service costs	0.1	0.1
Current year actuarial loss	3.7	23.3
Effect of exchange rates	1.7	(1.5)
Amortization of prior service (costs) credits	(0.2)	(0.3)
Amortization of actuarial loss	(8.8)	(39.2)
Total recognized in other comprehensive income	(3.5)	(17.6)
Total recognized in net periodic benefit cost and other comprehensive income (loss)	1.8	20.1
Estimated prior service (cost) credits	(0.1)
Estimated actuarial gains (losses)	(9.3)
Other Benefits [Member]
Amounts recognized in other comprehensive income (loss):
Prior service costs	9.5	12.0
Actuarial loss	(14.7)	(16.3)
Subtotal	(5.2)	(4.3)
Deferred taxes	1.9	1.6
Net amount recognized	(3.3)	(2.7)
Changes recognized in other comprehensive income (loss):
Current year prior service costs	0.0	0.0
Current year actuarial loss	(0.1)	(0.7)
Effect of exchange rates	0.0	0.0
Amortization of prior service (costs) credits	2.4	3.1
Amortization of actuarial loss	(1.4)	(1.4)
Total recognized in other comprehensive income	0.9	1.0
Total recognized in net periodic benefit cost and other comprehensive income (loss)	0.0	$ (0.5)
Estimated prior service (cost) credits	1.4
Estimated actuarial gains (losses)	$ (1.3)