Property, Plant and Equipment (Tables)

6 Months Ended

Jun. 30, 2019

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment and Accumulated Depreciation

The historical costs of our property, plant and equipment and related accumulated depreciation balances were as follows at the dates indicated:

	Estimated Useful Life in Years			June 30, 2019		December 31, 2018
Plants, pipelines and facilities (1)		3-45	(5)	$	44,578.5	$	42,371.0
Underground and other storage facilities (2)		5-40	(6)		3,700.2		3,624.2
Transportation equipment (3)		3-10			195.0		187.1
Marine vessels (4)		15-30			877.2		828.6
Land					365.1		359.5
Construction in progress					3,230.6		3,526.8
Total					52,946.6		50,897.2
Less accumulated depreciation					12,857.5		12,159.6
Property, plant and equipment, net				$	40,089.1	$	38,737.6

(1)	Plants, pipelines and facilities include processing plants; NGL, natural gas, crude oil and petrochemical and refined products pipelines; terminal loading and unloading facilities; buildings; office furniture and equipment; laboratory and shop equipment and related assets.
(2)	Underground and other storage facilities include underground product storage caverns; above ground storage tanks; water wells and related assets.
(3)	Transportation equipment includes tractor-trailer tank trucks and other vehicles and similar assets used in our operations.
(4)	Marine vessels include tow boats, barges and related equipment used in our marine transportation business.
(5)	In general, the estimated useful lives of major assets within this category are: processing plants, 20-35 years; pipelines and related equipment, 5-45 years; terminal facilities, 10-35 years; buildings, 20-40 years; office furniture and equipment, 3-20 years; and laboratory and shop equipment, 5-35 years.
(6)	In general, the estimated useful lives of assets within this category are: underground storage facilities, 5-35 years; storage tanks, 10-40 years; and water wells, 5-35 years.

Depreciation Expense and Capitalized Interest

The following table summarizes our depreciation expense and capitalized interest amounts for the periods indicated:

	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2019			2018			2019			2018
Depreciation expense (1)		$	389.3		$	361.0		$	769.9		$	692.8
Capitalized interest (2)			32.8			27.1			69.0			85.3

(1)

Depreciation expense is a component of “Costs and expenses” as presented on our Unaudited Condensed Statements of Consolidated Operations.

(2)

We capitalize interest costs incurred on funds used to construct property, plant and equipment while the asset is in its construction phase.  The capitalized interest is recorded as part of the asset to which it relates and is amortized over the asset’s estimated useful life as a component of depreciation expense.  When capitalized interest is recorded, it reduces interest expense from what it would be otherwise.

AROs

ARO liability balance, December 31, 2018	$	126.3
Liabilities incurred		0.7
Liabilities settled		(0.3	)
Revisions in estimated cash flows		(4.8	)
Accretion expense		4.0
ARO liability balance, June 30, 2019	$	125.9