Income Taxes Uncertain tax positions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Uncertain tax positions	(4.00%)	1.00%	0.00%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 3.7	$ 14.6
Unrecognized Tax Benefits	4.1	42.2	$ 48.9	$ 49.9
Tax positions taken in current year	0.0	0.1	0.0
Tax positions taken in prior years	0.9	1.3	0.4
Tax positions taken in current year	0.0	0.0	0.0
Tax positions taken in prior years	(0.5)	(8.1)	0.0
Settlements during the year	(34.7)	0.0	0.0
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	(3.8)	0.0	$ (1.4)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.2	1.0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 0.1	$ 4.7

Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income tax contingencies. Includes, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 740
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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