v3.26.3
SEGMENT INFORMATION - Schedule of Segment Information (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 4 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]            
Revenue $ 839 $ 745 $ 2,442 $ 2,259 $ 3,281 $ 3,004
Salaries and employee benefits 378 349 1,128 1,084 1,506 1,433
Operating supplies and expenses 176 150 546 471 722 621
Purchased transportation 74 65 235 200 309 265
Depreciation and amortization 38 43 114 125 152 168
Insurance and claims 15 14 44 42 59 56
Operating taxes and licenses 6 6 17 17 23 23
Separation and other costs 22 0 105 30 127 30
Total other (income) expense 16 (32) 49 (101) 65 (133)
Provision for income taxes 31 37 57 100 88 137
Net income $ 83 $ 113 147 291 230 404
Reportable Segment            
Segment Reporting [Line Items]            
Revenue     2,442 2,259 3,281 3,004
Salaries and employee benefits     1,128 1,084 1,506 1,433
Operating supplies and expenses     546 471 722 621
Purchased transportation     235 200 309 265
Depreciation and amortization     114 125 152 168
Insurance and claims     44 42 59 56
Operating taxes and licenses     17 17 23 23
Separation and other costs     105 30 127 30
Total other (income) expense     49 (101) 65 (133)
Provision for income taxes     57 100 88 137
Total significant segment expenses     2,295 1,968 3,051 2,600
Net income     $ 147 $ 291 $ 230 $ 404