Restructuring Charges (Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 51	$ 69	$ 128	$ 110
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	51		128
2016 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2		12
2016 Plan [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	48		111
2016 Plan [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	1		5
2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	36		108
2016 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	2		12
2016 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	33		91
2016 Plan [Member] | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	1		5
2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	15		20
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	15		20
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		69		110
2015 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		0		3
2015 Plan [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		68		101
2015 Plan [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		1		6
2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		19		59
2015 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		0		3
2015 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		18		50
2015 Plan [Member] | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		1		6
2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		50		51
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		50		51
2015 Plan [Member] | Other Restructuring [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		0		0
North America [Member] | 2016 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	15		39
North America [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	5		24
North America [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	10		15
North America [Member] | 2015 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		21		29
North America [Member] | 2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		4		12
North America [Member] | 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		17		17
Middle East, North Africa, and Asia [Member] | 2016 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	11		20
Middle East, North Africa, and Asia [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	9		18
Middle East, North Africa, and Asia [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	2		2
Middle East, North Africa, and Asia [Member] | 2015 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		29		35
Middle East, North Africa, and Asia [Member] | 2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		6		11
Middle East, North Africa, and Asia [Member] | 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		23		24
Europe, Sub-Sahara Africa, Russia [Member] | 2016 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	10		25
Europe, Sub-Sahara Africa, Russia [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	8		23
Europe, Sub-Sahara Africa, Russia [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	2		2
Europe, Sub-Sahara Africa, Russia [Member] | 2015 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		14		21
Europe, Sub-Sahara Africa, Russia [Member] | 2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		5		12
Europe, Sub-Sahara Africa, Russia [Member] | 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		9		9
Latin America [Member] | 2016 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	12		27
Latin America [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	11		26
Latin America [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	$ 1		$ 1
Latin America [Member] | 2015 Plan [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		4		16
Latin America [Member] | 2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		3		15
Latin America [Member] | 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		$ 1		$ 1