v3.25.4
Sales Of Receivables (Equipment Installment and AT&T Revolving Programs) (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Asset Pledged as Collateral without Right    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Receivables, Fair Value Disclosure $ 425  
Equipment Installment Program | Guarantee Obligation    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Guarantee obligation 410 $ 301
Equipment Installment Program | Accounts payable and accrued liabilities | Guarantee Obligation    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Guarantee obligation 216 150
Equipment Installment Program | Deferred Purchase Price Receivables    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Deferred purchase price receivable 2,067 3,185
Equipment Installment Program | Deferred Purchase Price Receivables | Prepaid Expenses and Other Current Assets    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Deferred purchase price receivable 1,338 $ 1,906
Revolving Receivables Program | Maximum Amount    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revolving agreement, transfer amount $ 2,940