Background (Details) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		24 Months Ended
	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Dec. 31, 2023 USD ($) divestiture	Jan. 01, 2024	Jan. 01, 2023 USD ($)	Oct. 03, 2022 state
Change in Accounting Estimate [Line Items]
Number of business divestitures | divestiture					3
Accumulated deficit	$ 18,047		$ 18,047		$ 17,907
Book overdraft balance	$ 0		$ 0		$ 0
Diluted loss per common share (in dollars per share) | $ / shares	$ (0.15)	$ (0.08)	$ (0.14)	$ (8.45)
Change in Accounting Method Accounted for as Change in Estimate
Change in Accounting Estimate [Line Items]
Depreciation	$ (16)		$ (48)
Depreciation, net of tax	$ (12)		$ (36)
Diluted loss per common share (in dollars per share) | $ / shares	$ 0.01		$ 0.03
Fiber Network Assets
Change in Accounting Estimate [Line Items]
Property, plant and equipment, useful life (in years)					25 years	30 years
Correction of Error from Understatement of Revenues and Network Expenses Prior to 2021
Change in Accounting Estimate [Line Items]
Accumulated deficit		$ 63		$ 63			$ 63
Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations | ILEC Business
Change in Accounting Estimate [Line Items]
Number of states in which the business is conducted | state								20