Sale Of Equipment Installment Receivable (Equipment Installment and WarnerMedia Programs) (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Payable And Accrued Liabilities, Current			$ 43,955		$ 43,955		$ 43,184
Guarantee Obligations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Payable And Accrued Liabilities, Current			152		152		196
Guarantee Obligation			427		427		439
Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Supplemental Deferred Purchase Price			352	$ 335	922	$ 1,161
Other Assets [Member] | Deferred Purchase Price [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other Assets			2,300		2,300		2,370
Other Current Assets [Member] | Deferred Purchase Price [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other Assets			1,605		1,605		$ 1,448
WarnerMedia [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement Amount With Purchaser To Transfer Financial Assets Accounted For As Sales	$ 2,600	$ 1,400			4,000
Agreement Amount With Purchaser To Transfer Financial Assets Accounted For As Sales, Outstanding At A Point In Time			3,456		3,456
Receivables pledged as collateral			$ 3,147		$ 3,147