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Tax year that remains open to examination under enacted tax laws, in CCYY format.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of (increase) decrease reasonably possible in the estimated upper bound of the unrecognized tax benefit for a tax position taken or expected to be taken.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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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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-Name Accounting Standards Codification

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Amount of expense 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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Income Taxes, Additional Disclosures (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure
Range of potential change in unrecognized tax benefits due to state income tax positions and their resolution and expiration of statutes of limitations within the next year	$ 10.0
Net accrued interest and penalties, total	16.2	12.4
Accrued interest and penalties related to unrecognized income tax benefits	$ 3.4	$ 0.7	$ (1.5)
Federal
Income Tax Disclosure
Open tax years	2012
State
Income Tax Disclosure
Open tax years	2010