Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Activities
Net income	$ 470.6	$ 502.5	$ 556.8
Adjustments to reconcile net income to net cash provided (required) by operating activities
Depreciation and amortization	276.8	248.0	228.7
Impairment of properties	5.3	8.2	0.0
Deferred and noncurrent income tax charges (benefits)	45.1	14.0	2.0
Restructuring expense, net of cash paid	5.6	0.0	0.0
Accretion of asset retirement obligations	3.4	3.2	3.0
Amortization of discount on marketable securities	0.0	(0.2)	(0.4)
(Gains) losses from sale of assets	2.8	4.5	0.8
Net (increases) decrease in noncash operating working capital	(33.1)	32.8	(42.1)
Other operating activities - net	37.4	34.6	35.2
Net cash provided (required) by operating activities	813.9	847.6	784.0
Investing Activities
Property additions	(439.6)	(458.1)	(335.6)
Proceeds from sale of assets	2.4	2.0	2.4
Investment in marketable securities	0.0	0.0	(12.8)
Redemptions of marketable securities	0.0	11.5	24.0
Other investing activities - net	1.2	(1.2)	(1.6)
Net cash provided (required) by investing activities	(436.0)	(445.8)	(323.6)
Financing Activities
Purchase of treasury stock	(649.9)	(445.7)	(333.2)
Dividends paid	(41.5)	(36.8)	(33.4)
Borrowings of debt	2,982.3	707.0	8.0
Repayments of debt	(2,654.4)	(666.7)	(23.4)
Debt issuance costs	(9.0)	0.0	0.0
Amounts related to share-based compensation	(23.5)	(30.4)	(21.1)
Net cash provided (required) by financing activities	(396.0)	(472.6)	(403.1)
Net increase (decrease) in cash, cash equivalents and restricted cash	(18.1)	(70.8)	57.3
Cash, cash equivalents and restricted cash at January 1	47.0	117.8	60.5
Cash, cash equivalents and restricted cash at December 31	$ 28.9	$ 47.0	$ 117.8