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Income Taxes Deferred Tax Asset Valuation Allowance (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015
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Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | $ 322.2 | $ 105.1
Federal Net Operating Losses [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 37.8 | 0.0
Federal Tax Credits [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 40.5 | 24.8
Federal Temporary Differences [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 141.2 | 0.0
Federal Deferred Tax Assets [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 219.5 | 24.8
State Net Operating Losses [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 77.9 | 61.8
State Tax Credits [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 13.3 | 13.8
State Temporary Differences [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 6.5 | 3.3
State Deferred Tax Assets [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | 97.7 | 78.9
Foreign Deferred Tax Assets [Member] |  |
Valuation Allowance [Line Items] |  |
Valuation allowance for deferred tax assets | $ 5.0 | $ 1.4

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32537-109319 + Details
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