Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 24,742	$ 25,169
Less Allowance for credit losses	896	1,252
Accounts receivable, net	23,846	$ 23,917
Device payment plan agreement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	13,287
Less Allowance for credit losses	504
Accounts receivable, net	12,783
Wireless service
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	4,872
Less Allowance for credit losses	130
Accounts receivable, net	4,742
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	6,583
Less Allowance for credit losses	262
Accounts receivable, net	$ 6,321