Sales Of Receivables (Equipment Installment and AT&T Revolving Programs) (Narrative) (Details) - Equipment Installment Program - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Guarantee Obligation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Guarantee obligation	$ 345	$ 371
Accounts payable and accrued liabilities | Guarantee Obligation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Guarantee obligation	64	101
Deferred Purchase Price Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price receivable	1,740	3,177
Deferred Purchase Price Receivable | Prepaid and other current assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price receivable	$ 821	$ 2,123