XML 34 R13.htm IDEA: XBRL DOCUMENT v3.20.4
Property, Plant and Equipment
 12 Months Ended
Dec. 31, 2020
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment Property, Plant and Equipment
  December 31, 2020December 31, 2019
(Millions of dollars)Estimated Useful LifeCostNetCostNet
Land $609.5 $609.5 $598.6 $598.6 
Pipeline and terminal facilities
16 to 25 years
79.8 43.5 77.5 43.7 
Retail gasoline stations
3 to 50 years
2,179.7 1,123.2 2,034.4 1,073.6 
Buildings
20 to 45 years
66.7 48.5 60.5 44.9 
Other
3 to 20 years
123.3 42.9 115.5 46.5 
  $3,059.0 $1,867.6 $2,886.5 $1,807.3 

Depreciation expense of $160.0 million, $151.2 million and $132.5 million was recorded for the years ended December 31, 2020, 2019 and 2018, respectively.