Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 117.8	$ 60.5
Marketable securities, current	7.1	17.9
Accounts receivable—trade, less allowance for doubtful accounts of $1.3 in 2023 and $0.3 in 2022, respectively	336.7	281.7
Inventories, at lower of cost or market	341.2	319.1
Prepaid expenses and other current assets	23.7	47.6
Total current assets	826.5	726.8
Marketable securities, non-current	4.4	4.4
Property, plant and equipment, at cost less accumulated depreciation and amortization of $1,694.2 in 2023 and $1,553.1 in 2022 respectively	2,571.8	2,459.3
Operating lease right of use assets, net	452.1	449.6
Intangible assets, net of amortization	139.8	140.4
Goodwill	328.0	328.0
Other assets	17.5	14.7
Total assets	4,340.1	4,123.2
Current liabilities
Current maturities of long-term debt	15.0	15.0
Trade accounts payable and accrued liabilities	834.7	839.2
Income taxes payable	23.1	0.0
Total current liabilities	872.8	854.2
Long-term debt, including capitalized lease obligations	1,784.7	1,791.9
Deferred income taxes	329.5	327.4
Asset retirement obligations	46.1	43.3
Non-current operating lease liabilities	450.3	444.2
Deferred credits and other liabilities	27.8	21.5
Total liabilities	3,511.2	3,482.5
Stockholders' Equity
Preferred Stock, par $0.01, (authorized 20,000,000 shares, none outstanding)	0.0	0.0
Common Stock, par $0.01, (authorized 200,000,000 shares, 46,767,164 shares issued at December 31, 2023 and 2022, respectively)	0.5	0.5
Treasury stock (25,490,133 and 25,017,324 shares held at December 31, 2022 and 2021, respectively)	(2,957.8)	(2,633.3)
Additional paid in capital (APIC)	508.1	518.9
Retained earnings	3,278.1	2,755.1
Accumulated other comprehensive income (AOCI)	0.0	(0.5)
Total stockholders' equity	828.9	640.7
Total liabilities and stockholders' equity	$ 4,340.1	$ 4,123.2

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1