Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Corporate statutory tax rate			35.00%
Percentage of deduction for cost			100.00%
Reduction in net deferred tax liabilities	$ 87.2
Valuation allowance on foreign tax credits			$ 9.5
Transition tax expense on foreign tax credit utilization			$ 10.3
Expected percentage of deduction for cost per year			20.00%
Tax credit carryforward netted with unrecognized tax benefits	15.7		$ 15.7	$ 19.3
Valuation allowances	47.4		47.4	17.3
Difference between book and tax basis of undistributed foreign earnings			17.7
Estimated future taxable income to realize foreign tax credits			$ 74.8
Estimated future taxable income to realize foreign tax credits, expiration year			2022
Unremitted earnings not taxed			$ 245.5
Income tax reconciliation foreign withholding taxes			7.6
Unrecognized tax benefits	53.4		53.4	86.9	$ 150.6	$ 142.6
UTB if recognized, would impact the reported effective tax rate	36.9		36.9
UTB if recognized, would impact the reported effective tax rate, net of federal benefit	35.2		35.2
Interest and penalty exposure reported as accrued income tax	3.5		$ 3.5
Minimum [Member]
Income Taxes [Line Items]
Number of open tax years subject to audit			3 years
Maximum [Member]
Income Taxes [Line Items]
Number of open tax years subject to audit			6 years
State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	664.6		$ 664.6	760.6
Valuation allowances	19.4		19.4
Estimated future taxable income to utilize deferred tax assets			506.8
UTB decrease due to uncertain tax positions	0.1		$ 0.1
State [Member] | Minimum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration date			2018
State [Member] | Maximum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration date			2036
Federal [Member]
Income Taxes [Line Items]
Tax credit carryforward gross				22.1
Tax credit carryforward netted with unrecognized tax benefits	15.7		$ 15.7	$ 19.3
Valuation allowances	10.3		10.3
UTB increase due to uncertain tax positions	$ 2.8		$ 2.8
Federal [Member] | Minimum [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year			2018
Federal [Member] | Maximum [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year			2022
Scenario, Forecast [Member]
Income Taxes [Line Items]
Corporate statutory tax rate		21.00%