Guarantor Consolidating Financial Statements - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended			24 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (Loss)	$ 50.3	$ 83.5	$ 104.4	$ 95.3	$ 75.3	$ 135.4	$ 81.2	$ 45.3	$ 333.5	$ 337.2	$ 576.4
Depreciation and Amortization									447.2	430.6	330.3
Deferred Income Taxes									5.8	(5.5)	(346.8)
Amount of Postretirement Expense Greater (Less) Than Funding									41.5	(4.7)	(127.1)
Gain on the Sale of Assets, net									0.0	38.6	3.7
Equity in Net Income (Loss) of Subsidiaries									0.0	0.0	0.0
Gain on the Sale of Assets									0.0	(38.6)	(3.7)
Other, Net									19.8	56.7	7.1
Changes in Operating Assets and Liabilities									(186.2)	(1,126.2)	(652.0)
Net Cash Provided by (Used in) Operating Activities									661.6	(350.5)	(215.8)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital Spending									330.9	378.8	240.9
Packaging Machinery Spending									(22.0)	(16.4)	(19.2)
Acquisition of Businesses, Net of Cash Acquired									(54.5)	(89.4)	(189.4)
Cash Receipts on Sold Receivables									343.6	1,476.7	806.1
Beneficial Interest Obtained in Exchange for Proceeds									(155.9)	(345.5)	(97.4)
Proceeds Received from Sale of Assets, Net of Selling Costs									0.0	49.4	7.9
Other, Net									(4.6)	(6.9)	1.0
Net Cash (Used in) Provided by Investing Activities									(224.3)	689.1	268.1
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Issuance of Debt									300.0	0.0	0.0
Payments on Debt									(36.5)	(152.4)	(25.0)
Borrowings under Revolving Credit Facilities									2,497.5	1,876.9	1,202.9
Payments on Revolving Credit Facilities									(2,865.1)	(1,787.5)	(1,090.8)
Membership Distributions									(248.5)	(241.9)	0.0
Membership Distribution									0.0	0.0	(150.3)
Debt Issuance Cost									5.0	7.9	0.0
Other, Net									(3.2)	2.1	(6.6)
Net Cash Used In Financing Activities									(360.8)	(310.7)	(69.8)
EFFECT OF EXCHANGE RATE CHANGES ON CASH									1.7	(1.5)	2.5
Net Increase in Cash and Cash Equivalents									78.2	26.4	(15.0)
Cash and Cash Equivalents at Beginning of Year				70.5				44.1	70.5	44.1	59.1	$ 44.1
CASH AND CASH EQUIVALENTS AT END OF YEAR	148.7				70.5				148.7	70.5	44.1	148.7
Issuer
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash Receipts on Sold Receivables											565.7
Combined Guarantor Subsidiaries
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of Businesses, Net of Cash Acquired											0.0
Cash Receipts on Sold Receivables											0.0
Reportable Legal Entities | Issuer
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (Loss)									333.5	337.2	576.4
Depreciation and Amortization									386.8	354.5	260.8
Deferred Income Taxes									0.8	0.1	(341.8)
Amount of Postretirement Expense Greater (Less) Than Funding									46.1	1.6	(113.8)
Gain on the Sale of Assets, net											3.7
Equity in Net Income (Loss) of Subsidiaries									(56.0)	(49.7)	(25.9)
Gain on the Sale of Assets										(38.6)
Other, Net									19.9	57.0	7.5
Changes in Operating Assets and Liabilities									(97.8)	(417.7)	(382.9)
Net Cash Provided by (Used in) Operating Activities									633.3	244.4	(23.4)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital Spending									288.0	349.9	193.2
Packaging Machinery Spending									(20.9)	(11.0)	(19.1)
Acquisition of Businesses, Net of Cash Acquired									(2.0)	(88.3)	(127.0)
Cash Receipts on Sold Receivables									251.8	782.8
Beneficial Interest Obtained in Exchange for Proceeds									(150.0)	(320.0)	(90.0)
Proceeds Received from Sale of Assets, Net of Selling Costs										49.4	7.9
Other, Net									(57.1)	(4.2)	(15.5)
Net Cash (Used in) Provided by Investing Activities									(266.2)	58.8	128.8
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Issuance of Debt									300.0
Payments on Debt									(36.5)	(152.4)	(25.0)
Borrowings under Revolving Credit Facilities									2,457.2	1,827.5	1,103.4
Payments on Revolving Credit Facilities									(2,786.2)	(1,717.3)	(1,026.6)
Membership Distributions									(248.5)	(241.9)
Membership Distribution											(150.3)
Debt Issuance Cost									5.0	7.9
Other, Net									(3.2)	2.1	(6.6)
Net Cash Used In Financing Activities									(322.2)	(289.9)	(105.1)
EFFECT OF EXCHANGE RATE CHANGES ON CASH									0.0	0.0	0.0
Net Increase in Cash and Cash Equivalents									44.9	13.3	0.3
Cash and Cash Equivalents at Beginning of Year				14.5				1.2	14.5	1.2	0.9	1.2
CASH AND CASH EQUIVALENTS AT END OF YEAR	59.4				14.5				59.4	14.5	1.2	59.4
Reportable Legal Entities | Combined Guarantor Subsidiaries
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (Loss)									0.0	0.0	(3.3)
Depreciation and Amortization									0.0	0.0	4.8
Deferred Income Taxes									0.0	0.0	(1.1)
Amount of Postretirement Expense Greater (Less) Than Funding									0.0	0.0	0.0
Gain on the Sale of Assets, net											0.0
Equity in Net Income (Loss) of Subsidiaries									3.5	3.7	6.1
Gain on the Sale of Assets										0.0
Other, Net									0.0	0.0	0.0
Changes in Operating Assets and Liabilities									(3.5)	(3.7)	(7.7)
Net Cash Provided by (Used in) Operating Activities									0.0	0.0	(1.2)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital Spending									0.0	0.0	0.0
Packaging Machinery Spending									0.0	0.0	0.0
Acquisition of Businesses, Net of Cash Acquired									0.0	0.0
Cash Receipts on Sold Receivables									0.0	0.0
Beneficial Interest Obtained in Exchange for Proceeds									0.0	0.0	0.0
Proceeds Received from Sale of Assets, Net of Selling Costs										0.0	0.0
Other, Net									0.0	0.0	0.0
Net Cash (Used in) Provided by Investing Activities									0.0	0.0	0.0
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Issuance of Debt									0.0
Payments on Debt									0.0	0.0	0.0
Borrowings under Revolving Credit Facilities									0.0	0.0	0.0
Payments on Revolving Credit Facilities									0.0	0.0	0.0
Membership Distributions									0.0	0.0
Membership Distribution											0.0
Debt Issuance Cost									0.0	0.0
Other, Net									0.0	0.0	0.0
Net Cash Used In Financing Activities									0.0	0.0	0.0
EFFECT OF EXCHANGE RATE CHANGES ON CASH									0.0	0.0	0.0
Net Increase in Cash and Cash Equivalents									0.0	0.0	(1.2)
Cash and Cash Equivalents at Beginning of Year				0.0				0.0	0.0	0.0	1.2	0.0
CASH AND CASH EQUIVALENTS AT END OF YEAR	0.0				0.0				0.0	0.0	0.0	0.0
Reportable Legal Entities | Combined Nonguarantor Subsidiaries
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (Loss)									52.5	46.0	23.1
Depreciation and Amortization									60.4	76.1	64.7
Deferred Income Taxes									5.0	(5.6)	(3.9)
Amount of Postretirement Expense Greater (Less) Than Funding									(4.6)	(6.3)	(13.3)
Gain on the Sale of Assets, net											0.0
Equity in Net Income (Loss) of Subsidiaries									0.0	0.0	0.0
Gain on the Sale of Assets										0.0
Other, Net									(0.1)	(0.3)	(0.4)
Changes in Operating Assets and Liabilities									(84.9)	(704.8)	(261.4)
Net Cash Provided by (Used in) Operating Activities									28.3	(594.9)	(191.2)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital Spending									42.9	28.9	47.7
Packaging Machinery Spending									(1.1)	(5.4)	(0.1)
Acquisition of Businesses, Net of Cash Acquired									(52.5)	(1.1)	(62.4)
Cash Receipts on Sold Receivables									91.8	693.9	240.4
Beneficial Interest Obtained in Exchange for Proceeds									(5.9)	(25.5)	(7.4)
Proceeds Received from Sale of Assets, Net of Selling Costs										0.0	0.0
Other, Net									0.0	(2.7)	0.0
Net Cash (Used in) Provided by Investing Activities									(10.6)	630.3	122.8
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Issuance of Debt									0.0
Payments on Debt									0.0	0.0	0.0
Borrowings under Revolving Credit Facilities									40.3	49.4	99.5
Payments on Revolving Credit Facilities									(78.9)	(70.2)	(64.2)
Membership Distributions									0.0	0.0
Membership Distribution											0.0
Debt Issuance Cost									0.0	0.0
Other, Net									52.5	0.0	16.5
Net Cash Used In Financing Activities									13.9	(20.8)	51.8
EFFECT OF EXCHANGE RATE CHANGES ON CASH									1.7	(1.5)	2.5
Net Increase in Cash and Cash Equivalents									33.3	13.1	(14.1)
Cash and Cash Equivalents at Beginning of Year				56.0				42.9	56.0	42.9	57.0	42.9
CASH AND CASH EQUIVALENTS AT END OF YEAR	89.3				56.0				89.3	56.0	42.9	89.3
Consolidating Eliminations
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (Loss)									(52.5)	(46.0)	(19.8)
Depreciation and Amortization									0.0	0.0	0.0
Deferred Income Taxes									0.0	0.0	0.0
Amount of Postretirement Expense Greater (Less) Than Funding									0.0	0.0	0.0
Gain on the Sale of Assets, net											0.0
Equity in Net Income (Loss) of Subsidiaries									52.5	46.0	19.8
Gain on the Sale of Assets										0.0
Other, Net									0.0	0.0	0.0
Changes in Operating Assets and Liabilities									0.0	0.0	0.0
Net Cash Provided by (Used in) Operating Activities									0.0	0.0	0.0
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital Spending									0.0	0.0	0.0
Packaging Machinery Spending									0.0	0.0	0.0
Acquisition of Businesses, Net of Cash Acquired									0.0	0.0	0.0
Cash Receipts on Sold Receivables									0.0	0.0	0.0
Beneficial Interest Obtained in Exchange for Proceeds									0.0	0.0	0.0
Proceeds Received from Sale of Assets, Net of Selling Costs										0.0	0.0
Other, Net									52.5	0.0	16.5
Net Cash (Used in) Provided by Investing Activities									52.5	0.0	16.5
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Issuance of Debt									0.0
Payments on Debt									0.0	0.0	0.0
Borrowings under Revolving Credit Facilities									0.0	0.0	0.0
Payments on Revolving Credit Facilities									0.0	0.0	0.0
Membership Distributions									0.0	0.0
Membership Distribution
Debt Issuance Cost									0.0	0.0
Other, Net									(52.5)	0.0	(16.5)
Net Cash Used In Financing Activities									(52.5)	0.0	(16.5)
EFFECT OF EXCHANGE RATE CHANGES ON CASH									0.0	0.0	0.0
Net Increase in Cash and Cash Equivalents									0.0	0.0	0.0
Cash and Cash Equivalents at Beginning of Year				$ 0.0				$ 0.0	0.0	0.0	0.0	0.0
CASH AND CASH EQUIVALENTS AT END OF YEAR	$ 0.0				$ 0.0				$ 0.0	$ 0.0	$ 0.0	$ 0.0