Restructuring Charges (Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 34	$ 22	$ 140	$ 150
2016 Plan
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	34	22	140	150
2016 Plan | Operating Segments | North America
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	1	5	24	44
2016 Plan | Operating Segments | Middle East, North Africa, and Asia
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	20	5	29	25
2016 Plan | Operating Segments | Europe, Sub-Sahara Africa, Russia
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2	0	31	25
2016 Plan | Operating Segments | Latin America
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9	10	25	37
2016 Plan | Corporate and Research and Development
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2	2	29	14
2016 Plan | Core Regional Segments
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	32	20	109	131
2016 Plan | Land Drilling Rigs
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0	0	2	5
2016 Plan | Employee Severance
Restructuring Cost and Reserve [Line Items]
Severance costs	15	18	71	126
2016 Plan | Employee Severance | North America
Restructuring Cost and Reserve [Line Items]
Severance costs	1	5	3	29
2016 Plan | Employee Severance | Middle East, North Africa, and Asia
Restructuring Cost and Reserve [Line Items]
Severance costs	4	4	12	22
2016 Plan | Employee Severance | Europe, Sub-Sahara Africa, Russia
Restructuring Cost and Reserve [Line Items]
Severance costs	2	(2)	10	21
2016 Plan | Employee Severance | Latin America
Restructuring Cost and Reserve [Line Items]
Severance costs	7	9	20	35
2016 Plan | Employee Severance | Corporate and Research and Development
Restructuring Cost and Reserve [Line Items]
Severance costs	1	2	24	14
2016 Plan | Employee Severance | Core Regional Segments
Restructuring Cost and Reserve [Line Items]
Severance costs	14	16	45	107
2016 Plan | Employee Severance | Land Drilling Rigs
Restructuring Cost and Reserve [Line Items]
Severance costs	0	0	2	5
2016 Plan | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	19	4	69	24
2016 Plan | Other Restructuring | North America
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	0	0	21	15
2016 Plan | Other Restructuring | Middle East, North Africa, and Asia
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	16	1	17	3
2016 Plan | Other Restructuring | Europe, Sub-Sahara Africa, Russia
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	0	2	21	4
2016 Plan | Other Restructuring | Latin America
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	2	1	5	2
2016 Plan | Other Restructuring | Corporate and Research and Development
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	1	0	5	0
2016 Plan | Other Restructuring | Core Regional Segments
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	18	4	64	24
2016 Plan | Other Restructuring | Land Drilling Rigs
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	$ 0	$ 0	$ 0	$ 0