Credit Losses on Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2024

Credit Loss [Abstract]

Activity on allowance for credit losses

The following table presents the activity of our allowance for credit losses by accounts receivable portfolio:

	Business		Mass Markets	Total
	(Dollars in millions)
Balance at December 31, 2021	$	19	19	38
Provision for expected losses	13		47	60
Write-offs charged against the allowance	(14)		(50)	(64)
Recoveries collected	2		—	2
Balance at December 31, 2022	20		16	36
Provision for expected losses	20		46	66
Write-offs charged against the allowance	(26)		(43)	(69)
Recoveries collected	—		1	1
Balance at December 31, 2023	14		20	34
Provision for expected losses	9		36	45
Write-offs charged against the allowance	(10)		(42)	(52)
Recoveries collected	—		2	2
Balance at December 31, 2024	$	13	16	29