Properties

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]


			Accumulated		Net Book		Depreciation
December 31, 2020	Cost		Depreciation		Value		Rate (1)
	($ in millions)

Land	$	2,394	$	—	$	2,394	—

Roadway:
Rail and other track material	7,153		(1,892)		5,261		2.35	%
Ties	5,685		(1,601)		4,084		3.41	%
Ballast	2,973		(774)		2,199		2.76	%
Construction in process	297		—		297		—
Other roadway	14,320		(3,926)		10,394		2.71	%
Total roadway	30,428		(8,193)		22,235

Equipment:
Locomotives	5,478		(1,911)		3,567		3.56	%
Freight cars	2,780		(1,023)		1,757		2.59	%
Computers and software	732		(391)		341		9.86	%
Construction in process	333		—		333		—
Other equipment	1,094		(399)		695		4.70	%
Total equipment	10,417		(3,724)		6,693

Other property	91		(68)		23		2.24	%

Total properties	$	43,330	$	(11,985)	$	31,345


			Accumulated		Net Book		Depreciation
December 31, 2019	Cost		Depreciation		Value		Rate (1)
	($ in millions)

Land	$	2,385	$	—	$	2,385	—

Roadway:
Rail and other track material	7,024		(1,905)		5,119		2.30	%
Ties	5,536		(1,496)		4,040		3.37	%
Ballast	2,868		(723)		2,145		2.72	%
Construction in process	360		—		360		—
Other roadway	14,261		(3,786)		10,475		2.71	%
Total roadway	30,049		(7,910)		22,139

Equipment:
Locomotives	5,973		(2,112)		3,861		3.66	%
Freight cars	2,988		(1,148)		1,840		2.45	%
Computers and software	732		(355)		377		9.68	%
Construction in process	291		—		291		—
Other equipment	1,082		(388)		694		4.89	%
Total equipment	11,066		(4,003)		7,063

Other property	96		(69)		27		1.05	%

Total properties	$	43,596	$	(11,982)	$	31,614

(1)Composite annual depreciation rate for the underlying assets, excluding the effects of the amortization of any deficiency (or excess) that resulted from our depreciation studies.

In 2020, we sold $88 million of natural resource assets that were included in “Other current assets” on the Consolidated Balance Sheet at December 31, 2019. We recorded a $49 million impairment loss in 2019 related to these assets, which is reflected in “Gains and losses on properties” in the Consolidated Statement of Cash Flows for the year ended December 31, 2019.

Loss on Asset Disposal

In 2020, we sold 703 locomotives deemed excess and no longer needed for railroad operations. We evaluated these locomotive retirements and concluded they were abnormal (see Note 1). Accordingly, we recorded a $385 million loss to adjust their carrying amount to their estimated fair value, which resulted in a $97 million tax benefit.

Capitalized Interest

Total interest cost incurred on debt was $639 million, $620 million, and $574 million during 2020, 2019 and 2018, respectively, of which $14 million, $16 million, and $17 million was capitalized during 2020, 2019 and 2018, respectively.