Debt - Narrative (Details) - USD ($) $ in Millions		6 Months Ended
Sep. 01, 2021	Jun. 30, 2021
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 26
Redemption price rate		100.00%
Subsequent event
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 14
Redemption price rate	100.00%
6.875% Senior Notes
Debt Instrument [Line Items]
Amount redeemed		$ 225
Interest rate		6.875%
7.0% Senior Notes
Debt Instrument [Line Items]
Amount redeemed		$ 300
Interest rate		7.00%
7.25% 2063 Senior Notes \| UScellular
Debt Instrument [Line Items]
Amount redeemed		$ 275
Interest rate		7.25%
5.5% 2070 Senior Notes \| UScellular
Debt Instrument [Line Items]
Interest rate		5.50%
Redemption price rate		100.00%
Principal amount		$ 500
Long-term debt		484
Debt issuance costs		16
7.25% 2064 Senior Notes \| UScellular
Debt Instrument [Line Items]
Amount redeemed		$ 300
Interest rate		7.25%
Unamortized debt issuance costs		$ 10
Redemption price rate		100.00%
6.625% Senior Notes \| Subsequent event
Debt Instrument [Line Items]
Amount redeemed	$ 116
Interest rate	6.625%
6.95% Senior Notes \| UScellular \| Subsequent event
Debt Instrument [Line Items]
Amount redeemed	$ 342
Interest rate	6.95%

Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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