Earnings Per Share Earnings Per Share, Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Payments of Ordinary Dividends, Common Stock	$ 8.2	$ 7.1
Common Stock, Dividends, Per Share, Cash Paid	$ 0.45	$ 0.40
Treasury Stock, Shares, Acquired	83,265	405,259
Treasury Stock Acquired, Average Cost Per Share	$ 76.85	$ 74.05
Treasury Stock, Value, Acquired, Cost Method	$ 6.4	$ 30.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 116.9