v3.26.3
Restructuring Costs - Schedule of Restructuring Plan Expenses Incurred (Details)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
Sep. 30, 2026
USD ($)
Restructuring Cost and Reserve [Line Items]    
Restructuring Incurred Cost Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag Total restructuring plan expenses Total restructuring plan expenses
UScellular Acquisition Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses $ 39 $ 214
Incurred to Date 325 325
UScellular Acquisition Restructuring Initiatives | Contract termination costs    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 19 111
Incurred to Date 143 143
UScellular Acquisition Restructuring Initiatives | Severance costs    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 9 66
Incurred to Date 129 129
UScellular Acquisition Restructuring Initiatives | Network decommissioning    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 11 37
Incurred to Date 53 53
Network Optimization Restructuring Initiatives    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 30 131
Incurred to Date 200 200
Network Optimization Restructuring Initiatives | Contract termination costs    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 9 49
Incurred to Date 54 54
Network Optimization Restructuring Initiatives | Network decommissioning    
Restructuring Cost and Reserve [Line Items]    
Total restructuring plan expenses 21 82
Incurred to Date $ 146 $ 146