Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Credit Quality Indicators (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Device payment plan agreement receivables, at amortized cost
Device payment plan agreement receivables, at amortized cost	$ 30,805	$ 31,308
Device payment plan agreement
Device payment plan agreement receivables, at amortized cost
2025	4,649
2024	15,412
2023 and prior	9,768
Device payment plan agreement receivables, at amortized cost	29,829
Gross write-offs
2025	22
2024	226
2023 and prior	123
Gross write-offs	371
Wireless Service Plan Receivables
Device payment plan agreement receivables, at amortized cost
2025	5,687
2024	248
Device payment plan agreement receivables, at amortized cost	5,935
Gross write-offs
2025	21
2024 and prior	123
Gross write-offs	144
New customers | Device payment plan agreement
Device payment plan agreement receivables, at amortized cost
2025	968
2024	2,776
2023 and prior	1,459
Device payment plan agreement receivables, at amortized cost	5,203
Gross write-offs
2025	22
2024	181
2023 and prior	61
Gross write-offs	264
Existing customers | Device payment plan agreement
Device payment plan agreement receivables, at amortized cost
2025	3,681
2024	12,636
2023 and prior	8,309
Device payment plan agreement receivables, at amortized cost	24,626
Gross write-offs
2025	0
2024	45
2023 and prior	62
Gross write-offs	$ 107