Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents
Cash and money market funds	$ 32.2	$ 22.9
Commercial paper	90.2	102.7
Total	122.4	125.6
Trade Receivables – Net
Trade receivables, gross	178.9	180.6
Allowance for doubtful receivables	(0.8)	(0.8)
Trade receivables – net	178.1	179.8
Inventories
Finished products	44.2	48.0
Work-in-process	98.5	85.6
Raw materials	81.0	75.0
Operating supplies	7.4	6.5
Total	231.1	215.1
Property, Plant and Equipment – Net
Land and improvements	21.4	21.4
Buildings and leasehold improvements	98.7	97.0
Machinery and equipment	783.6	755.6
Construction in progress	38.1	43.6
Property, plant and equipment – gross	941.8	917.6
Accumulated depreciation	(329.6)	(307.4)
Assets held for sale	1.6	1.6
Property, plant and equipment – net	613.8	611.8
Other Accrued Liabilities
Uncleared cash disbursements	3.5	4.8
Accrued income taxes and taxes payable	7.8	6.5
Accrued annual contribution to Salaried VEBA	0.0	2.1
Accrued interest	2.9	2.9
Other	33.0	27.7
Total	47.2	44.0
Long-Term Liabilities
Workers’ compensation accruals	25.9	24.6
Long-term environmental accrual	12.6	14.3
Other long-term liabilities	24.7	27.5
Total	63.2	66.4
Billed
Trade Receivables – Net
Trade receivables, gross	178.9	179.5
Unbilled
Trade Receivables – Net
Trade receivables, gross	$ 0.0	$ 1.1