Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2024

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

All intangible assets are being amortized over their estimated useful lives, as indicated below, with no estimated residual values. Intangible assets consists of the following:

	December 31, 2024						December 31, 2023
(Dollars in millions)	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Acquired intangible assets	$	1,087	$	(962)	$	125	$	1,087	$	(940)	$	147
Patents and licenses	14		(7)		7		10		(6)		4
Total intangible assets	$	1,101	$	(969)	$	132	$	1,097	$	(946)	$	151

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

The estimated annual amortization expense related to intangible assets for the subsequent five years is as follows:

(Dollars in millions) Year Ending December 31,	Estimated Annual Amortization
2025	$	22
2026	22
2027	19
2028	14
2029	14