Intangible Asset, Net

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Asset, Net

Intangible Assets, Net

Intangible assets, net of accumulated amortization, consisted of the following (in millions):

		December 31, 2023						December 31, 2022
	Estimated Useful Lives (Years)	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Customer contracts and relationships	1 – 29	$	2,789	$	(932)	$	1,857	$	2,817	$	(695)	$	2,122
Other agreements	15 – 70	30		(12)		18		35		(12)		23
Intangible assets (1)		$	2,819	$	(944)	$	1,875	$	2,852	$	(707)	$	2,145

(1)We include rights-of-way, which are intangible assets, within property and equipment. See Note 6 for a discussion of property and equipment.

Intangible assets that have finite lives are tested for impairment when events or circumstances indicate that the carrying value may not be recoverable. We did not recognize any impairments of finite-lived intangible assets during the three years ended December 31, 2023.

The majority of our finite-lived intangible assets are amortized under the declining balance method. Amortization expense for finite-lived intangible assets for the years ended December 31, 2023, 2022 and 2021 was $308 million, $254 million and $122 million, respectively. We estimate that our amortization expense related to finite-lived intangible assets for the next five years will be as follows (in millions):

2024	$	272
2025	$	249
2026	$	210
2027	$	187
2028	$	165