Sales Of Receivables (Equipment Installment and AT&T Revolving Programs) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Equipment Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables	$ 3,504	$ 3,714
Noncurrent notes and trade receivables	1,450	1,471
Outstanding portfolio of receivables derecognized from our consolidated balance sheets	11,909	12,027
Cash proceeds received, net of remittances	8,243	9,361
Equipment Installment | Notes receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	1,817	1,695
Equipment Installment | Trade receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	237	548
Revolving
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables	553	924
Noncurrent notes and trade receivables	0	0
Outstanding portfolio of receivables derecognized from our consolidated balance sheets	2,770	1,500
Cash proceeds received, net of remittances	2,770	1,500
Revolving | Notes receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	0	0
Revolving | Trade receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 553	$ 924