Asset Retirement Obligations and Accrued Environmental Costs (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Asset retirement obligations and accrued environmental costs

Note 10—Asset Retirement Obligations and Accrued Environmental Costs 

Asset retirement obligations and accrued environmental costs at December 31 were:

Millions of Dollars

2019

2018

Asset retirement obligations

$

6,206

7,908

Accrued environmental costs

171

178

Total asset retirement obligations and accrued environmental costs

6,377

8,086

Asset retirement obligations and accrued environmental costs due within one year*

(1,025)

(398)

Long-term asset retirement obligations and accrued environmental costs

$

5,352

7,688

*Classified as a current liability on the balance sheet under “Other accruals.” $

741

 million relates to assets which are held for sale as of

December 31, 2019. For additional information see Note 5—Asset Acquisitions and Dispositions.

Changes in overall asset retirement obligation changed

During 2019 and 2018, our overall ARO changed as follows:

Millions of Dollars

2019

2018

Balance at January 1

$

7,908

7,798

Accretion of discount

322

348

New obligations

155

657

Changes in estimates of existing obligations

50

(266)

Spending on existing obligations

(229)

(228)

Property dispositions

(1,920)

(161)

Foreign currency translation

(80)

(240)

Balance at December 31

$

6,206

7,908