Receivables and Related Allowance for Credit Losses - Schedule of Equipment Installment Plan Receivables by Credit Category (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, net of unamortized imputed discount	$ 5,824	$ 6,766
Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	2,106
Originated in 2023	2,099
Originated prior to 2023	303
EIP receivables, net of unamortized imputed discount	4,508
Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	638
Originated in 2023	578
Originated prior to 2023	100
EIP receivables, net of unamortized imputed discount	1,316
Current - 30 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, net of unamortized imputed discount	5,711
Current - 30 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	2,093
Originated in 2023	2,076
Originated prior to 2023	297
EIP receivables, net of unamortized imputed discount	4,466
Current - 30 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	612
Originated in 2023	539
Originated prior to 2023	94
EIP receivables, net of unamortized imputed discount	1,245
31 - 60 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, net of unamortized imputed discount	46
31 - 60 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	7
Originated in 2023	8
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	17
31 - 60 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	14
Originated in 2023	13
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	29
61 - 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, net of unamortized imputed discount	35
61 - 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	4
Originated in 2023	7
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	13
61 - 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	8
Originated in 2023	12
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	22
More than 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, net of unamortized imputed discount	32
More than 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	2
Originated in 2023	8
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	12
More than 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2024	4
Originated in 2023	14
Originated prior to 2023	2
EIP receivables, net of unamortized imputed discount	$ 20

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