CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net (loss) income	$ (969.9)	$ (11.3)	$ 327.9
Adjustments to reconcile net (loss) income to net cash and cash equivalents provided by (used for) operating activities:
Goodwill impairment	699.8	0.0	0.0
Gain on disposition of non-consolidated affiliate	0.0	(11.2)	0.0
Losses of non-consolidated affiliates	0.0	0.0	19.7
Losses on disposition of property, plant and equipment	0.0	0.0	2.0
Stock-based compensation	13.6	10.7	12.0
Depreciation and amortization	568.4	597.4	601.4
Deferred income taxes	(18.4)	(45.5)	35.6
Write-off of equipment and facility included in restructuring charges	0.0	58.9	2.6
Qualified pension plan contributions	(2.1)	(14.9)	(2.6)
Qualified pension plan income	11.4	9.3	15.0
Change in assets and liabilities:
Receivables	(0.3)	12.3	(46.3)
Income taxes receivable/payable	(11.2)	(10.7)	24.5
Inventories	28.6	13.0	(35.5)
Other current assets	(24.8)	7.4	0.2
Accounts payable and accrued liabilities	149.3	(11.0)	(14.5)
Other assets	(18.6)	(1.3)	(2.6)
Other noncurrent liabilities	12.8	30.5	4.3
Other operating activities	2.6	2.3	(5.9)
Net operating activities	418.4	617.3	907.8
Investing Activities
Capital expenditures	(298.9)	(385.6)	(385.2)
Payments under ethylene long-term supply contracts	461.0	0.0	0.0
Payments under other long-term supply contracts	(75.8)	0.0	0.0
Proceeds from disposition of property, plant and equipment	0.0	0.0	2.9
Proceeds from disposition of non-consolidated affiliate	0.0	20.0	0.0
Net investing activities	(835.7)	(365.6)	(382.3)
Long-term debt:
Borrowings	1,827.5	825.0	570.0
Repayments	1,307.2	744.2	946.1
Common stock repurchased and retired	0.0	(145.9)	(50.0)
Stock options exercised	1.9	1.7	3.4
Dividends paid	(126.3)	(129.3)	(133.6)
Debt issuance costs	(10.3)	(16.6)	(8.5)
Net financing activities	385.6	(209.3)	(564.8)
Effect of exchange rate changes on cash and cash equivalents	0.5	(0.3)	(0.3)
Net (decrease) increase in cash and cash equivalents	(31.2)	42.1	(39.6)
Cash and cash equivalents, beginning of year	220.9	178.8	218.4
Cash and cash equivalents, end of year	189.7	220.9	178.8
Cash paid (received) for interest and income taxes:
Interest, net	286.4	198.3	208.8
Income taxes, net of refunds	$ (9.6)	$ 36.3	$ 52.9