CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net income	$ 115.3	$ 140.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	34.7	30.7
Amortization	0.9	0.9
Stock-based compensation	5.0	8.5
Loss on disposal of plant	0.0	9.4
Asset impairments	0.6	1.9
Other non-cash items, net	(3.7)	(6.5)
Changes in assets and liabilities	(34.6)	(46.8)
Net cash provided by operating activities	118.2	138.1
Cash flows from investing activities:
Capital expenditures	(90.6)	(82.1)
Net cash used in investing activities	(90.6)	(82.1)
Cash flows from financing activities:
Repayments of long-term debt	(0.6)	(0.6)
Dividend payments	(14.7)	(14.1)
Proceeds from stock-based compensation awards	14.8	13.5
Employee stock purchase plan contributions	2.0	1.8
Shares purchased under share repurchase program	(267.0)	(60.1)
Shares repurchased for employee tax withholdings	(5.4)	(11.5)
Other, net	(0.1)	0.0
Net cash used in financing activities	(271.0)	(71.0)
Effect of exchange rates on cash	(8.7)	7.0
Net decrease in cash and cash equivalents	(252.1)	(8.0)
Cash, including cash equivalents at beginning of period	853.9	894.3
Cash, including cash equivalents at end of period	$ 601.8	$ 886.3