Narrative (Details) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) year	Dec. 31, 2014 USD ($)
NOL and Tax Credit Carryforwards [Line Items]
Amount	$ 274.0	$ 291.4		$ 274.0	$ 291.4
Number of Years in Cumulative Loss Profit Position | year						3
Valuation allowance				(14.5)	171.5	$ 74.5
Deferred tax asset valuation allowance charge		22.5	$ (173.1)
Valuation allowance applicable to other comprehensive income				(10.1)	130.4	121.7
Benefit from re-measurement of indefinite lived deferred tax liabilities				2.6
Benefit from decrease in deferred tax asset valuation allowance				1.5
Change in federal tax rate and law change	(4.1)			(4.1)	0.0	0.0
Foreign income taxable due to legislative changes				100.0
Goodwill impairment				36.6	0.0	0.0
Increase in deferred tax assets	468.9	730.6		468.9	730.6
Increase in deferred tax liabilities	471.0	734.2		471.0	734.2
Accumulated other comprehensive loss, net of tax	1,027.8	1,093.7		1,027.8	1,093.7	1,014.5	$ 931.4
Income tax refunds received				7.1	10.5	63.3
Deferred taxes for foreign withholding taxes	2.2			2.2
Federal and State Deferred Tax Assets [Member]
NOL and Tax Credit Carryforwards [Line Items]
Deferred tax asset valuation allowance charge					165.8	68.4
Accumulated Deferred Tax Asset Valuation Allowance [Member]
NOL and Tax Credit Carryforwards [Line Items]
Valuation allowance applicable to other comprehensive income				0.0	45.6	0.0
Accumulated other comprehensive loss, net of tax	$ 28.8	45.6		28.8	45.6	$ 0.0	$ 0.0
Federal [Member]
NOL and Tax Credit Carryforwards [Line Items]
Income tax refunds received				$ 3.2	7.3
Restatement Adjustment [Member]
NOL and Tax Credit Carryforwards [Line Items]
Increase in deferred tax assets		48.9			48.9
Increase in deferred tax liabilities		$ 48.9			$ 48.9