Sales Of Receivables (Equipment Installment and AT&T Revolving Programs) (Narrative) (Details) - Equipment Installment Program - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Guarantee Obligation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Guarantee obligation	$ 399	$ 419
Accounts payable and accrued liabilities | Guarantee Obligation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Guarantee obligation	55	73
Deferred Purchase Price Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price receivable	2,451	2,318
Deferred Purchase Price Receivable | Prepaid and other current assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price receivable	$ 1,395	$ 1,278