Changes in Shareholders' Equity Changes in Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,983.6
Net Loss	(0.3)
Other Comprehensive Income	17.1	$ 66.4
Cash Dividends and Dividend Equivalents to Shareholders ($0.24 per share)	12.3
Equity-based Compensation Cost	2.5
Equity-based Awards, Net of Shares Exchanged	0.9
Stockholders' Equity Attributable to Parent	$ 1,975.2
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 0.5