UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash Flows From Operating Activities
Net income	$ 45.0	$ 282.8
Loss from discontinued operations, net of income taxes	0.7	1.3
Income from continuing operations, net of income taxes	45.7	284.1
Adjustments to reconcile income from continuing operations, net of income taxes to net cash provided by operating activities:
Depreciation, depletion and amortization	79.8	76.3
Noncash interest expense, net	1.3	1.6
Deferred income taxes	8.5	46.0
Noncash share-based compensation	2.0	1.7
Asset impairment	0.0	2.0
Net gain on disposals	(2.1)	(1.9)
Noncash income from port and rail capacity assignment	0.0	(9.2)
Net loss on early debt extinguishment	0.0	6.8
Loss (income) from equity affiliates	3.7	(1.8)
Foreign currency option contracts	5.7	2.2
Changes in current assets and liabilities:
Accounts receivable	46.8	70.8
Inventories	(52.6)	(35.4)
Other current assets	13.6	43.5
Accounts payable and accrued expenses	(169.5)	(39.6)
Collateral arrangements	151.3	(45.9)
Asset retirement obligations	0.4	2.5
Workers’ compensation obligations	(0.1)	(0.9)
Postretirement benefit obligations	(15.4)	(14.4)
Pension obligations	0.0	0.4
Other, net	1.2	0.6
Net cash provided by continuing operations	120.3	389.4
Net cash used in discontinued operations	(1.3)	(3.1)
Net cash provided by operating activities	119.0	386.3
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development	(61.4)	(55.7)
Changes in accrued expenses related to capital expenditures	(6.8)	(1.6)
Proceeds from disposal of assets, net of receivables	2.4	2.9
Contributions to joint ventures	(202.8)	(206.2)
Distributions from joint ventures	193.2	202.0
Other, net	0.2	0.1
Net cash used in investing activities	(75.2)	(58.5)
Cash Flows From Financing Activities
Repayments of long-term debt	(2.2)	(2.7)
Payment of debt issuance and other deferred financing costs	(10.8)	(0.3)
Common stock repurchases	(83.1)	0.0
Repurchase of employee common stock relinquished for tax withholding	(3.4)	(13.2)
Dividends paid	(9.7)	0.0
Distributions to noncontrolling interests	(18.5)	(22.8)
Net cash used in financing activities	(127.7)	(39.0)
Net change in cash, cash equivalents and restricted cash	(83.9)	288.8
Cash, cash equivalents and restricted cash at beginning of period (1)	1,650.2	1,417.6
Cash, cash equivalents and restricted cash at end of period (2)	1,566.3	$ 1,706.4
Cash and cash equivalents	855.7
Restricted Cash	$ 710.6