Property, Plant and Equipment and Intangible Assets


	December 31, 2024			December 31, 2023			Estimated Useful Lives (In Years)
Gathering systems	$	11,575.0		$	10,858.3		5 to 20
Processing and fractionation facilities		9,543.3			8,285.5		5 to 25
Terminaling and storage facilities		1,469.1			1,403.9		5 to 25
Transportation assets		4,131.5			3,294.0		10 to 50
Other property, plant and equipment		537.7			430.5		3 to 50
Land		198.6			185.0		—
Construction in progress		1,702.9			1,456.1		—
Finance lease right-of-use assets		401.3			351.9		5 to 14
Property, plant and equipment		29,559.4			26,265.2
Accumulated depreciation, amortization and impairment		(11,496.7	)		(10,458.8	)
Property, plant and equipment, net	$	18,062.7		$	15,806.4

Intangible assets		4,378.0			4,378.0		10 to 20
Accumulated amortization and impairment		(2,400.6	)		(2,027.4	)
Intangible assets, net	$	1,977.4		$	2,350.6

For each of the years ended December 31, 2024, 2023 and 2022 depreciation expense was $1,049.8 million, $945.6 million and $853.8 million, respectively.

Intangible assets consist of customer contracts and customer relationships acquired in prior business combinations. The fair value of these acquired intangible assets were determined at the date of acquisition based on the present values of estimated future cash flows. Amortization expense attributable to these assets is recorded over the periods in which we benefit from services provided to customers.

For each of the years ended December 31, 2024, 2023 and 2022 amortization expense was $373.2 million, $384.0 million and $242.2 million, respectively.

The estimated annual amortization expense for intangible assets is approximately $326.0 million, $279.8 million, $252.2 million, $234.0 million and $214.1 million for each of the years 2025 through 2029. As of December 31, 2024, the weighted average amortization period for our intangible assets was approximately 10 years.

The changes in our intangible assets are as follows:


	December 31, 2024			December 31, 2023
Balance at beginning of period	$	2,350.6		$	2,734.6
Amortization		(373.2	)		(384.0	)
Balance at end of period	$	1,977.4		$	2,350.6