Receivables and Related Allowance for Credit Losses - Gross EIP Receivables by Credit Category (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	$ 7,829	$ 5,888
Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	3,933
Originated in 2020	892
Originated prior to 2020	23
Total EIP Receivables, net of unamortized imputed discounts	4,848
Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	2,486
Originated in 2020	487
Originated prior to 2020	8
Total EIP Receivables, net of unamortized imputed discounts	2,981
Current - 30 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	7,683
Current - 30 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	3,894
Originated in 2020	878
Originated prior to 2020	22
Total EIP Receivables, net of unamortized imputed discounts	4,794
Current - 30 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	2,419
Originated in 2020	464
Originated prior to 2020	6
Total EIP Receivables, net of unamortized imputed discounts	2,889
31 - 60 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	78
31 - 60 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	24
Originated in 2020	7
Originated prior to 2020	0
Total EIP Receivables, net of unamortized imputed discounts	31
31 - 60 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	37
Originated in 2020	10
Originated prior to 2020	0
Total EIP Receivables, net of unamortized imputed discounts	47
61 - 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	31
61 - 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	8
Originated in 2020	3
Originated prior to 2020	0
Total EIP Receivables, net of unamortized imputed discounts	11
61 - 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	15
Originated in 2020	5
Originated prior to 2020	0
Total EIP Receivables, net of unamortized imputed discounts	20
More than 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Total EIP Receivables, net of unamortized imputed discounts	37
More than 90 days past due \| Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	7
Originated in 2020	4
Originated prior to 2020	1
Total EIP Receivables, net of unamortized imputed discounts	12
More than 90 days past due \| Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Originated in 2021	15
Originated in 2020	8
Originated prior to 2020	2
Total EIP Receivables, net of unamortized imputed discounts	$ 25

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.

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+ References

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- Definition

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

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