v3.26.1
Variable Interest Entities - Income Statement (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Variable Interest Entity [Line Items]        
Lease Income $ 508,400,000 $ 368,800,000 $ 1,027,100,000 $ 728,400,000
Other Operating Income 51,100,000 41,200,000 94,000,000.0 81,700,000
Total revenues 580,100,000 430,500,000 1,163,800,000 852,100,000
Maintenance expense 151,800,000 104,500,000 292,500,000 208,000,000.0
Depreciation expense 166,500,000 106,900,000 335,700,000 210,500,000
Operating lease expense 7,400,000 7,100,000 14,800,000 14,700,000
Other operating expense 24,800,000 16,500,000 46,600,000 32,500,000
Selling, general and administrative expense 69,200,000 58,200,000 140,500,000 114,800,000
Total expenses (1) 419,700,000 293,200,000 830,100,000 580,500,000
Net gain on asset dispositions 69,700,000 40,500,000 120,700,000 73,900,000
Interest expense, net (143,000,000.0) (96,200,000) (294,000,000.0) (191,100,000)
Income taxes (26,000,000.0) (21,000,000.0) (47,200,000) (37,600,000)
Net Income 111,000,000.0 75,500,000 190,100,000 154,100,000
Income before income taxes 99,800,000 80,500,000 179,300,000 150,600,000
Cash paid for the acquisition of operating assets 200,500,000 219,000,000.0 4,720,500,000 515,300,000
Net proceeds from the issuance of debt     994,000,000.0 879,800,000
Cash paid for the repayment of debt     1,149,800,000 406,600,000
Payments of distributions to affiliates     49,900,000 0
Brookfield        
Variable Interest Entity [Line Items]        
Other Operating Income 2,800,000   5,600,000  
GABX        
Variable Interest Entity [Line Items]        
Depreciation expense
Variable Interest Entity, Primary Beneficiary | GABX        
Variable Interest Entity [Line Items]        
Total revenues 136,600,000 0 271,500,000 0
Total expenses (1) (108,600,000) 0 (208,800,000) 0
Net gain on asset dispositions 21,900,000 0 23,900,000 0
Interest expense, net (36,600,000) 0 (80,500,000) 0
Income taxes (2,500,000) 0 (4,400,000) 0
Net Income 10,800,000 0 1,700,000 0
Income before income taxes 13,300,000 $ 0 6,100,000 $ 0
Management fees $ 12,400,000   24,900,000  
Cash paid for the acquisition of operating assets     4,230,800,000  
Net proceeds from the issuance of debt     992,000,000.0  
Cash paid for the repayment of debt     1,077,900,000  
Proceeds from asset sales     166,400,000  
Variable Interest Entity, Primary Beneficiary | GABX | Brookfield        
Variable Interest Entity [Line Items]        
Payments of distributions to affiliates     49,900,000  
Variable Interest Entity, Primary Beneficiary | GABX | GATX        
Variable Interest Entity [Line Items]        
Payments of distributions to affiliates     $ 21,400,000