Equipment Installment Plans - Gross Receivables by Credit Category (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023 |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | $ 1,120 | $ 1,151 |
2021 | 19 | |
2022 | 351 | |
2023 | 579 | |
2024 | 171 | |
Unbilled | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 1,060 | 1,085 |
Billed | Current | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 43 | 43 |
Billed | Past Due | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 17 | 23 |
Lowest Risk | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 1,004 | 1,024 |
2021 | 18 | |
2022 | 328 | |
2023 | 510 | |
2024 | 148 | |
Lowest Risk | Unbilled | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 957 | 977 |
Lowest Risk | Billed | Current | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 38 | 35 |
Lowest Risk | Billed | Past Due | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 9 | 12 |
Lower Risk | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 93 | 100 |
2021 | 1 | |
2022 | 20 | |
2023 | 56 | |
2024 | 16 | |
Lower Risk | Unbilled | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 84 | 88 |
Lower Risk | Billed | Current | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 4 | 5 |
Lower Risk | Billed | Past Due | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 5 | 7 |
Slight Risk | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 18 | 21 |
2021 | 0 | |
2022 | 2 | |
2023 | 10 | |
2024 | 6 | |
Slight Risk | Unbilled | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 15 | 16 |
Slight Risk | Billed | Current | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 1 | 2 |
Slight Risk | Billed | Past Due | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 2 | 3 |
Higher Risk | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 5 | 6 |
2021 | 0 | |
2022 | 1 | |
2023 | 3 | |
2024 | 1 | |
Higher Risk | Unbilled | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 4 | 4 |
Higher Risk | Billed | Current | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | 0 | 1 |
Higher Risk | Billed | Past Due | | |
Financing Receivable, Credit Quality Indicator [Line Items] | | |
Equipment installment plan receivables, gross | $ 1 | $ 1 |