Income Tax Matters, Textuals (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency
Income tax provision	$ 12.0	$ 14.5	$ (163.8)	$ 23.9
Effective tax rate	37.20%	37.00%	37.60%	37.20%
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 1.9
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	5.80%
Tax Adjustments, Settlements, and Unusual Provisions	$ (1.8)
Effective Income Tax Rate Reconciliation, Tax Contingency, Foreign, Percent	(5.40%)
Refund adjustment from settlement	$ (9.3)		$ (9.3)
Effective Income Tax Rate Reconciliation, Amount expected to be received in the next 12 months			(1.1)
Gross unrecognized tax benefits	1.6		1.6		$ 2.2
Gross unrecognized tax benefits that would impact effective tax rate	0.5		$ 0.5		$ 1.1
Audit & Advanced Pricing Agreement
Income Tax Contingency
Refund adjustment from settlement						$ 10.4
Union VEBA
Income Tax Contingency
Income tax benefit on removal of Union VEBA net assets	$ 184.4