Income Taxes (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Current income taxes:          
Federal     $ 19 $ 40 $ 737
Foreign     (428) (423) (415)
State     (15) (14) 35
Total current     424 397 (357)
Deferred income taxes:          
Federal     286 (678) 1,343
Foreign     9 (31) 77
State     (28) (25) 81
Total deferred     267 (734) 1,501
Income tax benefit (provision) $ 306   (157) (1,131) 1,858
The United States and foreign components of income from continuing operations before income taxes [Abstract]          
United States     1,097 694 (6,636)
Foreign     717 (12) (989)
Income (loss) from continuing operations before income taxes     $ 1,814 $ 682 $ (7,625)
Reconciliations between the actual provision for income taxes on continuing operations [Abstract]          
United States statutory rate     21.00% 35.00% 35.00%
Impact of U.S. tax reform     (2.60%) 113.00% 0.00%
Venezuela adjustment     5.70% 36.60% 0.00%
Impact of foreign income taxed at different rates     (3.00%) (18.30%) (3.20%)
Valuation allowance against tax assets     (16.20%) (6.20%) (2.10%)
Undistributed foreign earnings     0.00% 3.80% (5.10%)
Adjustments of prior year taxes     2.00% (2.30%) 0.20%
State income taxes     1.90% 1.70% 1.00%
Domestic manufacturing deduction     0.00% 0.00% (1.30%)
Non-deductible acquisition costs     0.00% 0.00% 0.60%
Other items, net     (0.10%) 2.50% (0.70%)
Total effective tax rate on continuing operations     8.70% 165.80% 24.40%
Impairments and other charges [1]     $ 265 $ 647 $ 3,357
Gross deferred tax assets:          
Net operating loss carryforwards 1,466   1,466 1,370  
Foreign tax credit carryforwards 728   728 828  
Employee compensation and benefits 242   242 263  
Accrued Liabilities 101   101 97  
Other 404   404 416  
Total gross deferred tax assets 2,941   2,941 2,974  
Gross deferred tax liabilities:          
Depreciation and amortization 635   635 315  
Undistributed Foreign Earnings 2   2 242  
Other 64   64 56  
Total gross deferred tax liabilities 701   701 613  
Valuation allowances 913   913 1,173  
Net deferred income tax asset 1,327   1,327 1,188  
Unrecognized Tax Benefits          
Beginning Balance   $ 333 [2] 333 [2] 427 322
Change in prior year tax positions     32   44
Change in prior year tax positions       (108)  
Change in current year tax positions     63 24 129
Cash settlements with taxing authorities     (7) (6) (62)
Lapse of statute of limitations     (4) (4) (6)
Ending balance 417 [2],[3]   417 [2],[3] 333 [2] 427
Interest and Penalties          
Beginning balance   60 60 61 47
Change in prior year tax positions     11 0 20
Change in current year tax positions     0 2 3
Cash settlements with taxing authorities     (2) 0 (8)
Lapse of statute of limitations     (2) (3) (1)
Ending balance 67   67 60 61
Remaining balance if resolved in our favor would positively impact the effective tax rate 399   399 319  
Portion of unrecognized tax benefits that could be resolved within the next 12 months 21   21    
Impairments and other charges   265 265 647 $ 3,357 [1]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount 47        
Foreign Country          
Income Tax Contingency [Line Items]          
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 1,500   1,500    
Years 2018-2022 [Domain]          
Income Tax Contingency [Line Items]          
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 168   168    
Years 2024-2028 [Domain]          
Income Tax Contingency [Line Items]          
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 180   180    
Deferred Tax Assets, Tax Credit Carryforwards, Research and Foreign That Expire 805   805    
Years 2029-2038 [Domain]          
Income Tax Contingency [Line Items]          
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 786   786    
Deferred Tax Assets, Tax Credit Carryforwards, Research and Foreign That Expire 138   138    
VENEZUELA          
Reconciliations between the actual provision for income taxes on continuing operations [Abstract]          
Impairments and other charges [1]       647  
Interest and Penalties          
Accrued taxes portion of Venezuela investment write-down   $ 47      
All Other Countries [Domain]          
Interest and Penalties          
Remaining balance if resolved in our favor would positively impact the effective tax rate $ 18   $ 18 $ 9  
[1] Impairments and other charges are as follows:
-For the year ended December 31, 2018, the aggregate charge of $265 million represents a write-down of all of our remaining investment in Venezuela, consisting of receivables, fixed assets, inventory and other assets and liabilities.
-For the year ended December 31, 2017, the aggregate charge of $647 million represents a fair market value adjustment on our existing promissory note with our primary customer in Venezuela and a full reserve against our other accounts receivable with this customer.
-For the year ended December 31, 2016, the aggregate charge of $3.4 billion consisted of fixed asset impairments and write-offs, inventory write-downs, impairments of intangible assets, severance costs, country and facility closures, and other charges related to the energy downturn. This included $2.1 billion attributable to Completion and Production, $1.2 billion attributable to Drilling and Evaluation and $10 million attributable to Corporate and other.
[2] Includes $18 million as of December 31, 2018 and $9 million as of December 31, 2017 in foreign unrecognized tax benefits that would give rise to a United States tax credit. As of December 31, 2018 and December 31, 2017, approximately $399 million and $319 million, respectively, of unrecognized tax benefits would positively impact the effective tax rate and be recognized as additional tax benefits in our statement of operations if resolved in our favor.
[3] Includes $21 million that could be resolved within the next 12 months.