Income Taxes, Income Tax Examination (Details) (USD $) In Millions, unless otherwise specified				6 Months Ended
	Jun. 30, 2014 Internal Revenue Service (IRS) [Member]	Jan. 31, 2013 Internal Revenue Service (IRS) [Member]	Dec. 31, 2012 Internal Revenue Service (IRS) [Member]	Jun. 30, 2014 Internal Revenue Service (IRS) [Member] Minimum [Member]	Jun. 30, 2014 Internal Revenue Service (IRS) [Member] Maximum [Member]	Jun. 30, 2014 State and Local Jurisdiction [Member] Minimum [Member]	Jun. 30, 2014 State and Local Jurisdiction [Member] Maximum [Member]
Income Tax Examination [Line Items]
Tax years that remain subject to examination						2005	2012
Summary of income tax examinations [Abstract]
Deposits with the IRS			$ 60.4
Refund adjustment from settlement with taxing authority		42.3
Income tax years currently under examination				2010	2011
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	$ (0.7)