Condensed Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Activities
Net income	$ 47.8	$ 154.0
Adjustments to reconcile net income to net cash and cash equivalents provided by (used for) operating activities:
Depreciation and amortization	129.7	137.1
Stock-based compensation	4.4	3.7
Write-off of equipment and facility included in restructuring charges	0.0	12.8
Deferred income taxes	(13.9)	(11.0)
Qualified pension plan contributions	(0.3)	(0.8)
Qualified pension plan income	(6.0)	(5.1)
Change in:
Receivables	(37.5)	(4.5)
Income taxes receivable/payable	9.6	(11.9)
Inventories	31.2	(146.0)
Other current assets	3.6	(15.9)
Accounts payable and accrued liabilities	(95.9)	(66.1)
Other assets	(0.7)	(10.5)
Other noncurrent liabilities	5.7	6.0
Other operating activities	3.3	(4.3)
Net operating activities	81.0	37.5
Investing Activities
Capital expenditures	(44.3)	(61.4)
Payments under other long-term supply contracts	(28.5)	(9.3)
Other investing activities	(1.9)	(0.4)
Net investing activities	(74.7)	(71.1)
Long-term debt:
Borrowings	217.0	290.0
Repayments	(122.3)	(97.4)
Common stock repurchased and retired	(105.4)	(206.1)
Stock options exercised	19.8	11.2
Employee taxes paid for share-based payment arrangements	(10.5)	0.0
Dividends paid	(23.9)	(26.2)
Contributions received from noncontrolling interests	0.0	44.1
Net financing activities	(25.3)	15.6
Effect of exchange rate changes on cash and cash equivalents	(0.4)	0.0
Net decrease in cash and cash equivalents	(19.4)	(18.0)
Cash and cash equivalents, beginning of year	170.3	194.0
Cash and cash equivalents, end of period	150.9	176.0
Cash paid for interest and income taxes:
Interest, net	62.9	60.7
Income taxes, net of refunds	15.8	52.8
Non-cash investing activities:
Decrease in capital expenditures included in accounts payable and accrued liabilities	$ 9.6	$ 9.8