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
Income Taxes [Line Items]
Corporate statutory tax rate		21.00%	35.00%
Percentage of deduction for cost			100.00%
Net provisional income tax benefit	$ 82.5	$ 83.7
Operating Loss Carryforwards, Valuation Allowance		335.0
Tax credit carryforward netted with unrecognized tax benefits	15.7	19.1	$ 15.7
Valuation allowances	47.4	79.6	47.4
Difference between book and tax basis of undistributed foreign earnings		13.2
Estimated future taxable income to realize foreign tax credits		$ 91.0
Estimated future taxable income to realize foreign tax credits, expiration year		2028
Unremitted earnings not taxed		$ 208.0	245.5
Income tax reconciliation foreign withholding taxes		2.2	7.6
Unrecognized tax benefits	53.4	42.6	53.4	$ 86.9	$ 150.6
UTB if recognized, would impact the reported effective tax rate		23.5
UTB if recognized, would impact the reported effective tax rate, net of federal benefit		22.1
Interest and penalty exposure reported as accrued income tax		$ 2.6
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	$ 954.5	$ 664.6
Valuation allowances		47.3
Estimated future taxable income to utilize deferred tax assets		537.5
UTB decrease due to uncertain tax positions		$ 0.7
State [Member] | Minimum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration date		2019
State [Member] | Maximum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration date		2036
Federal [Member]
Income Taxes [Line Items]
Tax credit carryforward gross		$ 19.1		$ 15.7
Valuation allowances		19.1
UTB increase due to uncertain tax positions		$ 2.8
Federal [Member] | Minimum [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year		2019
Federal [Member] | Maximum [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year		2028