
	December 31, 2025				December 31, 2024
(In millions)	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Definite-lived intangibles
Customer relationships	$	825	$	574	$	795	$	497

Favorable leases	65		5		65		3
Total	$	891	$	580	$	860	$	499

We did not recognize any impairment of our identified intangible assets in 2025, 2024 and 2023.

Estimated future amortization expense for amortizable intangible assets for the next five years is as follows:


(In millions)	2026		2027		2028		2029		2030		Thereafter
Estimated amortization expense	$	59	$	59	$	46	$	36	$	36	$	75

Actual amounts of amortization expense may differ from estimated amounts due to changes in foreign currency exchange rates, additional intangible asset acquisitions, future impairment of intangible assets, accelerated amortization of intangible assets and other events.

Intangible asset amortization expense was $58 million, $57 million and $54 million for the years ended December 31, 2025, 2024 and 2023, respectively.