v3.26.1
Restructuring Costs - Schedule of Restructuring Plan Expenses Incurred (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2026
USD ($)
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses   $ 175
Restructuring Incurred Cost Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag Total restructuring plan expenses Total restructuring plan expenses
Incurred to Date $ 286 $ 286
UScellular Acquisition Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 90 175
Network Optimization Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 36 101
Incurred to Date 170 170
Contract termination costs    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses   92
Incurred to Date 124 124
Contract termination costs | UScellular Acquisition Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 51 92
Contract termination costs | Network Optimization Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 13 40
Incurred to Date 45 45
Severance costs    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses   57
Incurred to Date 120 120
Severance costs | UScellular Acquisition Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 31 57
Network decommissioning    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses   26
Incurred to Date 42 42
Network decommissioning | UScellular Acquisition Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 8 26
Network decommissioning | Network Optimization Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 23 61
Incurred to Date $ 125 $ 125