Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended				12 Months Ended			18 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 111.7	$ 12.9	$ 114.0	$ 69.3	$ 356.3	$ 408.7	$ 359.0
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on sale of business					0.0	10.6	27.0
Insurance recoveries received for property damage incurred from natural disaster					0.0	(79.6)	(10.9)
Dividends from affiliates					12.3	12.3	9.6
Restructuring expenses, net of cash paid					3.4	6.8	1.3
Provision for bad debts					8.1	4.5	4.7
Unrealized losses (gains), net on derivative contracts					0.3	(0.5)	1.3
Stock-based compensation expense					24.3	21.3	26.3
Depreciation and amortization					72.6	71.1	66.0
Deferred income taxes					7.2	16.6	25.2
Pension expense					10.5	106.1	8.8
Pension contributions					(3.3)	(1.8)	(20.6)
Other items, net					0.2	(0.4)	5.1
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts and notes receivable					26.5	(33.1)	(9.9)
Inventories					110.3	(63.9)	(84.2)
Other current assets					5.3	2.8	(0.2)
Accounts payable					(31.7)	(56.1)	102.2
Accrued expenses					35.4	(5.6)	5.9
Income taxes payable and receivable					(5.7)	(1.9)	(5.5)
Leases, net					2.1	2.1	0.0
Other, net					(6.1)	(10.5)	(3.6)
Net cash provided by operating activities					612.4	396.1	495.5
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment					1.0	1.3	0.1
Purchases of property, plant and equipment					(78.5)	(105.6)	(95.2)
Purchases of short-term investments					(2.2)	(2.9)	0.0
Net proceeds from sale of business					0.0	43.5	114.7
Insurance recoveries received for property damage incurred from natural disaster					0.0	79.6	10.9
Net cash used in investing activities					(79.7)	15.9	30.5
Cash flows from financing activities:
Short-term debt payments					(4.6)	(5.3)	(40.3)
Short-term debt proceeds					4.6	5.3	40.3
Asset securitization borrowings					91.0	184.5	155.0
Asset securitization payments					(376.0)	(167.5)	(163.0)
Long-term debt borrowings					600.0	0.0	0.0
Long-term debt payments					(10.8)	(6.4)	(3.0)
Borrowings from credit facility					1,576.0	2,367.0	2,435.9
Payments on credit facility					(2,081.5)	(2,269.5)	(2,395.0)
Payments of deferred financing costs					(7.5)	(0.3)	0.0
Proceeds from employee stock purchases					3.0	3.3	3.3
Repurchases of common stock					(100.0)	(400.0)	(450.2)
Repurchases of common stock to satisfy employee withholding tax obligations					(17.9)	(24.0)	(26.9)
Cash dividends paid					(118.1)	(110.5)	(93.9)
Net cash used in financing activities					(441.8)	(423.4)	(537.8)
(Decrease) increase in cash and cash equivalents					90.9	(11.4)	(11.8)
Effect of exchange rates on cash and cash equivalents					(4.3)	2.4	(10.1)
Cash and cash equivalents, beginning of year		$ 37.3		$ 46.3	37.3	46.3	68.2
Cash and cash equivalents, end of year	$ 123.9		$ 37.3		123.9	37.3	46.3	$ 37.3
Cash paid during the year for:
Interest, net					25.3	46.8	38.7
Income taxes (net of refunds)					90.3	83.0	90.0
Insurance recoveries received					0.0	243.2	124.3	$ 367.5
Income (Loss) from Equity Method Investments					$ (15.6)	$ (13.4)	$ (12.0)