Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax benefit favorably impacted			$ 83
Valuation allowance	$ 8	$ 8
Net deferred tax liabilities	1,247	1,198
Deferred income taxes, net	1,249	1,198
Deferred income tax assets, net	2
Unrecognized tax benefits that would impact effective income tax rate	422	432
Liabilities recorded for interest related to uncertain tax positions	60	40
Related Party Transaction [Line Items]
Income taxes paid (received)	556	539	(8)
Qwest Services Corporation
Related Party Transaction [Line Items]
Income taxes paid (received)	$ 556	$ 539	$ (8)

Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible impairment loss.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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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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