v3.26.1
Restructuring Costs - Schedule of Restructuring Plan Expenses Incurred (Details)
$ in Millions
 3 Months Ended
Mar. 31, 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
Incurred to Date $ 196
UScellular Acquisition Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 85
Network Optimization Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 65
Incurred to Date 134
Contract termination costs  
Restructuring Cost and Reserve [Line Items]  
Incurred to Date 73
Contract termination costs | UScellular Acquisition Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 41
Contract termination costs | Network Optimization Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 27
Incurred to Date 32
Severance costs  
Restructuring Cost and Reserve [Line Items]  
Incurred to Date 89
Severance costs | UScellular Acquisition Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 26
Network decommissioning  
Restructuring Cost and Reserve [Line Items]  
Incurred to Date 34
Network decommissioning | UScellular Acquisition Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 18
Network decommissioning | Network Optimization Restructuring Initiatives  
Restructuring Cost and Reserve [Line Items]  
Total restructuring plan expenses 38
Incurred to Date $ 102