Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Changes in Asset Retirement Obligations

The following shows the changes in asset retirement obligations:

years ended December 31 (in millions)	2023			2022			2021
Balance at beginning of year	$	380.0		$	306.8		$	153.8
Accretion expense		10.9			10.6			7.2
Liabilities incurred and liabilities assumed in business combinations		33.8			78.6			179.0
Liabilities settled		(27.7	)		(14.1	)		(5.2	)
Revisions in estimated cash flows		(12.5	)		(3.1	)		3.5
Liabilities reclassified from/(to) assets held for sale		15.8			1.2			(31.5	)
Balance at end of year	$	400.3		$	380.0		$	306.8

Schedule of Contractual Purchase Commitments

The Company’s contractual purchase commitments as of December 31, 2023 are as follows:

(in millions)
2024	$	247.2
2025		39.1
2026		28.7
2027		14.1
2028		14.4
Thereafter		51.7
Total	$	395.2

Schedule of Future Minimum Contracts of Affreightment and Royalty Commitments for All Noncancelable Agreements

Future minimum contracts of affreightment and royalty commitments for all noncancelable agreements that are not accounted for as leases on the Company’s consolidated balance sheet as of December 31, 2023 are as follows:

(in millions)	Contracts of Affreightment		Royalty Commitments
2024	$	16.9	$	26.4
2025		17.1		14.1
2026		17.4		11.7
2027		17.7		11.2
2028		—		8.0
Thereafter		—		77.4
Total	$	69.1	$	148.8