XML 158 R111.htm IDEA: XBRL DOCUMENT v3.22.4
Segment and Geographic Information - Reconciliation of Assets by Segment to Consolidated Total Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]      
Total assets $ 5,610.8 $ 4,949.8 $ 4,667.1
Property, plant, equipment and mine development, net 2,865.0 2,950.6 3,051.1
Operating lease right-of-use assets 26.9 35.5 49.9
Seaborne Mining      
Segment Reporting, Asset Reconciling Item [Line Items]      
Total assets 1,632.6 1,669.6 1,763.0
Property, plant, equipment and mine development, net 1,220.7 1,298.8 1,347.3
Operating lease right-of-use assets 20.5 19.2 30.8
U.S. Thermal Mining      
Segment Reporting, Asset Reconciling Item [Line Items]      
Total assets 1,359.4 1,318.5 1,345.3
Property, plant, equipment and mine development, net 1,217.5 1,209.5 1,258.8
Operating lease right-of-use assets 0.5 3.3 3.5
Corporate and Other (1)      
Segment Reporting, Asset Reconciling Item [Line Items]      
Total assets 2,618.8 1,961.7 1,558.8
Property, plant, equipment and mine development, net 426.8 442.3 445.0
Operating lease right-of-use assets $ 5.9 $ 13.0 $ 15.6