Restructuring Charges (Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 22	$ 49	$ 150	$ 159
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	22		150
2016 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	10		37
2016 Plan [Member] | Operating Segments [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0		25
2016 Plan [Member] | Operating Segments [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	5		25
2016 Plan [Member] | Operating Segments [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	5		44
2016 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2		14
2016 Plan [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	20		131
2016 Plan [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0		5
2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	18		126
2016 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	9		35
2016 Plan [Member] | Employee Severance [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	(2)		21
2016 Plan [Member] | Employee Severance [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	4		22
2016 Plan [Member] | Employee Severance [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	5		29
2016 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	2		14
2016 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	16		107
2016 Plan [Member] | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0		5
2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	4		24
2016 Plan [Member] | Other Restructuring [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	1		2
2016 Plan [Member] | Other Restructuring [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	2		4
2016 Plan [Member] | Other Restructuring [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	1		3
2016 Plan [Member] | Other Restructuring [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	0		15
2016 Plan [Member] | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	0		0
2016 Plan [Member] | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	4		24	60
2016 Plan [Member] | Other Restructuring [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	$ 0		$ 0
2015 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		49		159
2015 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		10		26
2015 Plan [Member] | Operating Segments [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		11		32
2015 Plan [Member] | Operating Segments [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		5		40
2015 Plan [Member] | Operating Segments [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		9		38
2015 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		8		11
2015 Plan [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		35		136
2015 Plan [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		6		12
2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		40		99
2015 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		10		25
2015 Plan [Member] | Employee Severance [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		9		21
2015 Plan [Member] | Employee Severance [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		3		14
2015 Plan [Member] | Employee Severance [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		4		16
2015 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		8		11
2015 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		26		76
2015 Plan [Member] | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		6		12
2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		9		60
2015 Plan [Member] | Other Restructuring [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		0		1
2015 Plan [Member] | Other Restructuring [Member] | Europe, Sub-Sahara Africa, Russia [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		2		11
2015 Plan [Member] | Other Restructuring [Member] | Middle East, North Africa, and Asia [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		2		26
2015 Plan [Member] | Other Restructuring [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		5		22
2015 Plan [Member] | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		0		0
2015 Plan [Member] | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		9
2015 Plan [Member] | Other Restructuring [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		$ 0		$ 0