Description of Company and Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of Goodwill Changes in the carrying amount of goodwill are detailed below by reportable segment.
Millions of dollars
Completion and Production
Drilling and Evaluation
Total
Balance at December 31, 2016:
$
1,679

$
735

$
2,414

Current year acquisitions
249

36

285

Purchase price adjustments for previous acquisitions
(6
)
—

(6
)
Balance at December 31, 2017:
$
1,922

$
771

$
2,693

Current year acquisitions
99

6

105

Purchase price adjustments for previous acquisitions
34

(7
)
27

Balance at December 31, 2018:
$
2,055

$
770

$
2,825