Stock-Based Compensation Stock-based Compensation (Expense) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock or Unit Option Plan Expense	$ 0.7	$ 1.1	$ 4.3
Restricted Stock or Unit Expense	29.2	36.1	28.6
Stock-based compensation expense	29.9	37.2	32.9
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	11.5	13.3	11.7
Allocated Share-based Compensation Expense, Net of Tax	$ 18.4	$ 23.9	$ 21.2