Fair Value Measurements, Level 3 Fair Value Input Reconciliation Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of activity for financial instruments classified as Level 3:
Fair value measurement at beginning of period	$ 0.6	$ 1.0	$ 1.1
Total realized/unrealized (loss) gain included in:
Cost of goods sold, excluding depreciation and amortization and other items and Unrealized loss (gain) on derivative instruments	3.9	(4.4)
Transactions involving Level 3 derivative contracts:
Purchases	(4.0)	2.8
Sales	0.0	0.0
Issuances	0.0	0.0
Settlements	7.5	(7.3)
Transactions involving Level 3 derivatives - net	3.5	(4.5)
Transfers in and (or) out of Level 3 valuation hierarchy	0.0	0.0
Fair value measurement at end of period	0.6	1.0
Total loss included in Unrealized loss (gain) on derivative instruments, attributable to the change in unrealized gain/loss relating to derivative contracts held at December 31:	$ (0.6)	$ (1.0)