Restructuring Charges (Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 49	$ 154	$ 159	$ 283
2015 Plan
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	49		159
2015 Plan | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	8		11
2015 Plan | North America [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9		38
2015 Plan | MENA/ Asia Pacific [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	5		40
2015 Plan | Europe/ SSA/ Russia [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	11		32
2015 Plan | Latin America [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	10		26
2015 Plan | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	35		136
2015 Plan | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	6		12
2015 Plan | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9		60
2015 Plan | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0		0
2015 Plan | Other Restructuring [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	5		22
2015 Plan | Other Restructuring [Member] | MENA/ Asia Pacific [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2		26
2015 Plan | Other Restructuring [Member] | Europe/ SSA/ Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	2		11
2015 Plan | Other Restructuring [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0		1
2015 Plan | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9		60
2015 Plan | Other Restructuring [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0		0
2015 Plan | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	40		99
2015 Plan | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	8		11
2015 Plan | Employee Severance [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	4		16
2015 Plan | Employee Severance [Member] | MENA/ Asia Pacific [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	3		14
2015 Plan | Employee Severance [Member] | Europe/ SSA/ Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9		21
2015 Plan | Employee Severance [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	10		25
2015 Plan | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	26		76
2015 Plan | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 6		$ 12
2014 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		154		283
2014 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		0		30
2014 Plan [Member] | North America [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		16		44
2014 Plan [Member] | MENA/ Asia Pacific [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		111		128
2014 Plan [Member] | Europe/ SSA/ Russia [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		9		36
2014 Plan [Member] | Latin America [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		13		36
2014 Plan [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		149		244
2014 Plan [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		5		9
2014 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		133		164
2014 Plan [Member] | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		0		2
2014 Plan [Member] | Other Restructuring [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		14		29
2014 Plan [Member] | Other Restructuring [Member] | MENA/ Asia Pacific [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		101		108
2014 Plan [Member] | Other Restructuring [Member] | Europe/ SSA/ Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		8		14
2014 Plan [Member] | Other Restructuring [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		6		7
2014 Plan [Member] | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		129		158
2014 Plan [Member] | Other Restructuring [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		4		4
2014 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		21		119
2014 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		0		28
2014 Plan [Member] | Employee Severance [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		2		15
2014 Plan [Member] | Employee Severance [Member] | MENA/ Asia Pacific [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		10		20
2014 Plan [Member] | Employee Severance [Member] | Europe/ SSA/ Russia [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		1		22
2014 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		7		29
2014 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		20		86
2014 Plan [Member] | Employee Severance [Member] | Land Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		$ 1		$ 5