Guarantor Condensed Consolidating Financial Statements - Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Current Assets:
Cash and Cash Equivalents	$ 110.2	$ 148.7
Receivables, Net	619.5	500.2
Inventories, Net	1,143.0	1,095.9
Intercompany Receivables	0.0	0.0
Other Current Assets	59.2	50.1
Total Current Assets	1,931.9	1,794.9
Property, Plant and Equipment, Net	3,288.1	3,253.8
Investment in Consolidated Subsidiaries	0.0	0.0
Goodwill	1,463.2	1,477.0
Other Assets	755.7	751.0
Total Assets	7,438.9	7,276.7
Current Liabilities:
Short-Term Debt and Current Portion of Long-Term Debt	49.1	50.4
Accounts Payable	625.7	716.1
Intercompany Payables	0.0	0.0
Other Accrued Liabilities	344.9	410.0
Total Current Liabilities	1,019.7	1,176.5
Long-Term Debt	3,434.5	2,809.9
Deferred Income Tax Liabilities	17.6	27.7
Other Noncurrent Liabilities	396.0	406.0
MEMBER'S INTEREST
Members' Equity	2,571.1	2,856.6	$ 2,758.0	$ 2,745.3
Total Liabilities and Member's Interest	7,438.9	7,276.7
Reportable Legal Entities | Issuer
Current Assets:
Cash and Cash Equivalents	50.3	59.4
Receivables, Net	179.3	154.0
Inventories, Net	874.3	843.6
Intercompany Receivables	871.1	781.4
Other Current Assets	38.8	29.7
Total Current Assets	2,013.8	1,868.1
Property, Plant and Equipment, Net	2,949.5	2,925.4
Investment in Consolidated Subsidiaries	204.5	203.1
Goodwill	1,299.8	1,299.8
Other Assets	550.0	536.9
Total Assets	7,017.6	6,833.3
Current Liabilities:
Short-Term Debt and Current Portion of Long-Term Debt	40.7	40.6
Accounts Payable	506.2	571.4
Intercompany Payables	0.0	0.0
Other Accrued Liabilities	253.7	315.0
Total Current Liabilities	800.6	927.0
Long-Term Debt	3,355.3	2,751.3
Deferred Income Tax Liabilities	4.2	4.8
Other Noncurrent Liabilities	286.4	293.6
MEMBER'S INTEREST
Members' Equity	2,571.1	2,856.6
Total Liabilities and Member's Interest	7,017.6	6,833.3
Reportable Legal Entities | Combined Guarantor Subsidiaries
Current Assets:
Cash and Cash Equivalents	0.0	0.0
Receivables, Net	0.0	0.0
Inventories, Net	0.0	0.0
Intercompany Receivables	204.4	203.0
Other Current Assets	0.0	0.0
Total Current Assets	204.4	203.0
Property, Plant and Equipment, Net	0.1	0.1
Investment in Consolidated Subsidiaries	9.0	15.5
Goodwill	0.0	0.0
Other Assets	0.0	0.0
Total Assets	213.5	218.6
Current Liabilities:
Short-Term Debt and Current Portion of Long-Term Debt	0.0	0.0
Accounts Payable	0.0	0.0
Intercompany Payables	0.0	0.0
Other Accrued Liabilities	0.0	0.0
Total Current Liabilities	0.0	0.0
Long-Term Debt	0.0	0.0
Deferred Income Tax Liabilities	0.0	0.0
Other Noncurrent Liabilities	0.0	0.0
MEMBER'S INTEREST
Members' Equity	213.5	218.6
Total Liabilities and Member's Interest	213.5	218.6
Reportable Legal Entities | Combined Nonguarantor Subsidiaries
Current Assets:
Cash and Cash Equivalents	59.9	89.3
Receivables, Net	440.2	346.2
Inventories, Net	268.7	252.3
Intercompany Receivables	0.0	0.0
Other Current Assets	20.4	20.4
Total Current Assets	789.2	708.2
Property, Plant and Equipment, Net	338.5	328.3
Investment in Consolidated Subsidiaries	0.0	0.0
Goodwill	163.4	177.2
Other Assets	205.7	214.1
Total Assets	1,496.8	1,427.8
Current Liabilities:
Short-Term Debt and Current Portion of Long-Term Debt	8.4	9.8
Accounts Payable	119.5	144.7
Intercompany Payables	1,327.6	1,137.4
Other Accrued Liabilities	91.2	95.0
Total Current Liabilities	1,546.7	1,386.9
Long-Term Debt	79.2	58.6
Deferred Income Tax Liabilities	13.4	22.9
Other Noncurrent Liabilities	109.6	112.4
MEMBER'S INTEREST
Members' Equity	(252.1)	(153.0)
Total Liabilities and Member's Interest	1,496.8	1,427.8
Consolidating Eliminations
Current Assets:
Cash and Cash Equivalents	0.0	0.0
Receivables, Net	0.0	0.0
Inventories, Net	0.0	0.0
Intercompany Receivables	(1,075.5)	(984.4)
Other Current Assets	0.0	0.0
Total Current Assets	(1,075.5)	(984.4)
Property, Plant and Equipment, Net	0.0	0.0
Investment in Consolidated Subsidiaries	(213.5)	(218.6)
Goodwill	0.0	0.0
Other Assets	0.0	0.0
Total Assets	(1,289.0)	(1,203.0)
Current Liabilities:
Short-Term Debt and Current Portion of Long-Term Debt	0.0	0.0
Accounts Payable	0.0	0.0
Intercompany Payables	(1,327.6)	(1,137.4)
Other Accrued Liabilities	0.0	0.0
Total Current Liabilities	(1,327.6)	(1,137.4)
Long-Term Debt	0.0	0.0
Deferred Income Tax Liabilities	0.0	0.0
Other Noncurrent Liabilities	0.0	0.0
MEMBER'S INTEREST
Members' Equity	38.6	(65.6)
Total Liabilities and Member's Interest	$ (1,289.0)	$ (1,203.0)