Receivables and Expected Credit Losses - Gross EIP Receivables by Credit Category (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	$ 5,888	$ 4,283
Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	2,677
Originated in 2019	538
Originated prior to 2019	126
Total EIP Receivables, net of unamortized imputed discounts	3,341
Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	2,089
Originated in 2019	430
Originated prior to 2019	28
Total EIP Receivables, net of unamortized imputed discounts	2,547
Current - 30 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	5,774
Current - 30 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	2,654
Originated in 2019	528
Originated prior to 2019	124
Total EIP Receivables, net of unamortized imputed discounts	3,306
Current - 30 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	2,035
Originated in 2019	407
Originated prior to 2019	26
Total EIP Receivables, net of unamortized imputed discounts	2,468
31 - 60 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	65
31 - 60 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	16
Originated in 2019	6
Originated prior to 2019	1
Total EIP Receivables, net of unamortized imputed discounts	23
31 - 60 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	30
Originated in 2019	12
Originated prior to 2019	0
Total EIP Receivables, net of unamortized imputed discounts	42
61 - 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	24
61 - 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	4
Originated in 2019	2
Originated prior to 2019	0
Total EIP Receivables, net of unamortized imputed discounts	6
61 - 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	13
Originated in 2019	5
Originated prior to 2019	0
Total EIP Receivables, net of unamortized imputed discounts	18
More than 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	25
More than 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	3
Originated in 2019	2
Originated prior to 2019	1
Total EIP Receivables, net of unamortized imputed discounts	6
More than 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2020	11
Originated in 2019	6
Originated prior to 2019	2
Total EIP Receivables, net of unamortized imputed discounts	$ 19

Financing Receivable, Originated, More than Two Years before Current Fiscal Year

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- Definition

Amount of financing receivable originated in current fiscal year.

+ References

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+ References

No definition available.

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- Definition

The receivable or note face amount less the unamortized discount or premium.

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