STATEMENTS OF CONSOLIDATED CASH FLOWS (UNAUDITED) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net (loss) income		$ (20.2)	$ 22.9
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation of property, plant and equipment		58.0	37.0
Amortization of definite-lived intangible assets		6.2	2.1
Amortization of debt premium and debt issuance costs		1.6	1.4
Deferred income taxes		(9.9)	14.8
Non-cash equity compensation		10.5	7.4
Loss (gain) on disposition of short-term investments			(0.7)
Non-cash asset impairment charge			0.5
Loss on extinguishment of debt		35.9
Loss on disposition of property, plant and equipment		0.1	0.1
Changes in operating assets and liabilities, net of effects of acquisition:
Trade and other receivables		(110.7)	43.4
Contract assets		(4.1)	19.8
Inventories		(52.5)	20.1
Prepaid expenses and other current assets		(3.9)	(5.7)
Accounts payable		105.8	(27.6)
Accrued liabilities		17.8	6.2
Annual variable cash contributions to Salaried VEBA		(1.7)	(2.9)
Long-term assets and liabilities, net		0.4	11.9
Net cash provided by operating activities		33.3	150.7
Cash flows from investing activities:
Capital expenditures		(29.9)	(37.2)
Cash payment for acquisition of Warrick, net of cash received – Note 4		(609.2)
Purchase of short-term investments			(39.1)
Purchase of equity securities		(0.4)	(0.5)
Proceeds from disposition of short-term investments			118.1
Proceeds from disposition of property, plant and equipment			0.3
Net cash (used in) provided by investing activities	[1]	(639.5)	41.6
Cash flows from financing activities:
Repayment of principal and redemption premium of 6.50% Senior Notes		(380.9)
Cash paid for debt issuance costs		(8.6)	(6.1)
Repayment of finance lease		(1.6)	(1.2)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(2.5)	(4.3)
Repurchase of common stock			(12.5)
Cash dividends and dividend equivalents paid		(35.0)	(32.7)
Net cash provided by financing activities		121.4	293.2
Net (decrease) increase in cash, cash equivalents and restricted cash during the period		(484.8)	485.5
Cash, cash equivalents and restricted cash at beginning of period		794.3	278.6
Cash, cash equivalents and restricted cash at end of period		309.5	764.1
4.50% Senior Notes
Cash flows from financing activities:
Issuance of Senior Notes		$ 550.0
6.50% Senior Notes
Cash flows from financing activities:
Issuance of Senior Notes			$ 350.0

[1] See Note 14 for supplemental cash flow information.