Other Financial Information - Other Current Assets, Net (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 67	$ 30
Contract acquisition costs	11	21
Contract fulfillment costs	30	26
Other	2	0
Total Other current assets, net	$ 110	77
Held-for-sale \| Lumen Mass Markets fiber-to-the-home business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other current assets, net		$ 8

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as current.

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