Condensed Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net income (loss)	$ 990.1	$ (936.9)
Adjustments to reconcile net income (loss) to net cash and cash equivalents provided by (used for) operating activities:
Goodwill impairment	0.0	699.8
Stock-based compensation	5.0	7.1
Loss on debt extinguishment	47.6	0.0
Depreciation and amortization	432.4	425.1
Deferred income taxes	(25.2)	(61.6)
Qualified pension plan contributions	(1.0)	(1.3)
Qualified pension plan income	(20.8)	(8.7)
Change in:
Receivables	(291.6)	57.0
Income taxes receivable/payable	64.8	(14.0)
Inventories	(161.8)	90.5
Other current assets	18.4	(7.2)
Accounts payable and accrued liabilities	157.9	52.9
Other assets	(9.2)	(4.1)
Other noncurrent liabilities	41.3	0.9
Other operating activities	3.8	5.8
Net operating activities	1,251.7	305.3
Investing Activities
Capital expenditures	(135.8)	(223.3)
Payments under ethylene long-term supply contracts	0.0	461.0
Payments under other long-term supply contracts	0.0	75.8
Net investing activities	(135.8)	(760.1)
Long-term debt:
Borrowings	390.0	1,212.5
Repayments	(1,241.1)	(591.8)
Debt early redemption premiums	(37.7)	0.0
Common stock repurchased and retired	(68.3)	0.0
Stock options exercised	58.3	0.5
Dividends paid	(95.8)	(94.7)
Debt issuance costs	(3.8)	(9.9)
Net financing activities	(998.4)	516.6
Effect of exchange rate changes on cash and cash equivalents	(1.1)	0.0
Net increase in cash and cash equivalents	116.4	61.8
Cash and cash equivalents, beginning of year	189.7	220.9
Cash and cash equivalents, end of period	306.1	282.7
Cash paid (received) for interest and income taxes:
Interest, net	218.2	179.3
Income taxes, net of refunds	104.5	(2.5)
Non-cash investing activities:
Decrease in capital expenditures included in accounts payable and accrued liabilities	$ 29.8	$ 46.2