Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Device payment plan agreement receivables, at amortized cost	$ 21,303	$ 17,959
Device payment plan agreement
Financing Receivable, Credit Quality Indicator [Line Items]
2021	16,528
2020	4,325
Prior to 2020 (1)	92
Device payment plan agreement receivables, at amortized cost	20,945
Device payment plan agreement | New customers
Financing Receivable, Credit Quality Indicator [Line Items]
2021	2,545
2020	589
Prior to 2020 (1)	10
Device payment plan agreement receivables, at amortized cost	3,144
Device payment plan agreement | Existing customers
Financing Receivable, Credit Quality Indicator [Line Items]
2021	13,983
2020	3,736
Prior to 2020 (1)	82
Device payment plan agreement receivables, at amortized cost	$ 17,801