Segment Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	$ 31	$ 51	$ 106	$ 128
Financing Receivable, Allowance for Credit Losses, Write-downs		84		84
Asset Write-Downs and Other Charges			34	164
Pressure Pumping Related Charges				35
Other Asset Impairment Charges		70
2016 Plan
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	31	51	106	128
2016 Plan | Drilling Rigs
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	1	1	2	5
2016 Plan | Corporate and Research and Development
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	1	2	27	12
2016 Plan | Europe, Sub-Sahara Africa, Russia | Operating Segments
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	8	10	29	25
2016 Plan | North America | Operating Segments
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	8	15	23	39
2016 Plan | Latin America | Operating Segments
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	8	12	16	27
2016 Plan | Middle East, North Africa, and Asia | Operating Segments
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	$ 5	$ 11	$ 9	20
Assets, Total [Member]
Segment Reporting Information [Line Items]
Asset Write-Downs and Other Charges				$ 92