Sale Of Equipment Installment Receivables (Equipment Installment and WarnerMedia Programs) (Details) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables:		$ 4,425	$ 5,994
Outstanding portfolio of receivables derecognized from our consolidated balance sheets		9,405	9,065
Cash proceeds received, net of remittances	[1]	6,920	6,508
Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable		2,528	3,457
Trade receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable		460	438
Other Noncurrent Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables:		1,437	2,099
WarnerMedia [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables:		3,147	0
Outstanding portfolio of receivables derecognized from our consolidated balance sheets		3,456	0
Cash proceeds received, net of remittances	[1]	3,456	0
WarnerMedia [Member] | Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable		0	0
WarnerMedia [Member] | Trade receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable		2,626	0
WarnerMedia [Member] | Other Noncurrent Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross receivables:		$ 521	$ 0

[1] Represents amounts to which financial institutions remain entitled, excluding the deferred purchase price.