Other Financial Information - Other Current Assets, Net (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Prepaid Expenses and Other Current Assets [Abstract]
Prepaid expenses	$ 420	$ 372
Income tax receivable	410	483
Materials, supplies and inventory	126	146
Contract assets	16	16
Other	15	22
Total other current assets, net	1,211	1,250
Held for sale | Mass Markets Fiber-to-the Home Business
Other Current Assets [Line Items]
Other current assets, net	15
Acquisition Costs
Prepaid Expenses and Other Current Assets [Abstract]
Contract costs	104	102
Fulfillment Costs
Prepaid Expenses and Other Current Assets [Abstract]
Contract costs	$ 120	$ 109