v3.25.2
Sales Of Receivables (Equipment Installment and AT&T Revolving Programs) (Narrative) (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Asset Pledged as Collateral without Right    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Receivables, Fair Value Disclosure $ 234  
Equipment Installment | Guarantee Obligation    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Guarantee obligation 263 $ 301
Equipment Installment | Accounts payable and accrued liabilities | Guarantee Obligation    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Guarantee obligation 140 150
Equipment Installment | Deferred Purchase Price Receivable    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Deferred purchase price receivable 1,990 3,185
Equipment Installment | Deferred Purchase Price Receivable | Prepaid and other current assets    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Deferred purchase price receivable 1,214 $ 1,906
Revolving Receivables Program | Maximum    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revolving agreement, transfer amount (up to) $ 2,940