Postretirement Benefit Plans - Change in Benefit Obligation, Plan Assets, Funded Status, and Balance Sheet Items (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in benefit obligation:
Benefit obligation at beginning of year	$ 110.0
Benefit obligation at end of year		$ 110.0
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.95%		3.80%
Discount rate	4.39%	3.95%
Expected long-term return on plan assets	6.25%	5.00%	5.00%
Change in benefit obligation:
Benefit obligation at beginning of year	$ 284.6	$ 515.6
Service cost	0.4	1.3	$ 2.9
Interest cost	10.9	16.7	21.7
International plan exchange rate change	(7.7)	18.0
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss)	(0.3)	(0.1)
Spinoff of TimkenSteel	(26.3)	(37.1)
Spinoff of Steel Change in Benefit Obligation	0.0	(229.8)
Benefit obligation at end of year	262.7	284.6	$ 515.6
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	$ 1.1	$ 0.0