Other Long-term Assets (Tables)

12 Months Ended

Dec. 31, 2019

Subclassifications of assets, liabilities and equities [abstract]

Schedule of Noncurrent Assets

($ millions)	2019	2018
Long-term investments	6.7	8.7
Other receivables	15.7	15.8
Reclamation fund	—	18.7
Other long-term assets	22.4	43.2

Disclosure of long-term investments

Long-term investments

($ millions)	2019		2018
Investments in public companies, beginning of year	8.7		65.1
Acquired through capital dispositions	—		112.6
Dispositions	—		(152.8	)
Unrealized loss recognized in other loss	(2.0	)	(16.2	)
Investments in public companies, end of year	6.7		8.7