Income Taxes Primary Impact on Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Refunds to be claimed on future amended U.S. federal returns for tax years 2014 and 2015		$ 44.6
Settlement of 2011 and 2012 income tax audits		23.4
Reversal of valuation allowance	$ 12.2	12.2	$ 66.0
Adoption of FASB ASU 2016-09	$ 7.5	$ 10.4
Reversal of valuation allowance from Jurisdiction-1			124.8
Establishment of valuation allowance from Jurisdiction-2			$ 57.2