Segment Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	$ 41		$ 70
Divestiture, professional and other fees portion	13		23
Other nonrecurring (income) expense	8		3
Assets	18,223				18,889
Operating Segments [Member]
Segment Reporting Information [Line Items]
Assets	17,856				18,543
Operating Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	6,675				7,297
Operating Segments [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Assets	3,006				3,022
Operating Segments [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Assets	3,132				3,106
Operating Segments [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Assets	3,163				3,211
Operating Segments [Member] | Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Assets	1,880				1,907
Corporate and Research and Development [Member]
Segment Reporting Information [Line Items]
Assets	367				346
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	41	[1]	(70)	[2]
UNITED STATES [Member] | Operating Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	5,700				6,100
North America, Excluding the United States [Member] | Operating Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	1,000				1,200
2015 Plan [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	41
2015 Plan [Member] | North America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	8
2015 Plan [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	6
2015 Plan [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	7
2015 Plan [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	12
2015 Plan [Member] | Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	5
2015 Plan [Member] | Operating Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	8
2015 Plan [Member] | Operating Segments [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	6
2015 Plan [Member] | Operating Segments [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	7
2015 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	12
2015 Plan [Member] | Corporate and Research and Development [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges	3
2014 Plan [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			70
2014 Plan [Member] | North America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			9
2014 Plan [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			4
2014 Plan [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			19
2014 Plan [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			19
2014 Plan [Member] | Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			3
2014 Plan [Member] | Operating Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			9
2014 Plan [Member] | Operating Segments [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			4
2014 Plan [Member] | Operating Segments [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			19
2014 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			19
2014 Plan [Member] | Corporate and Research and Development [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			16
2014 Plan [Member] | Employee Severance [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			66
2014 Plan [Member] | Employee Severance [Member] | North America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			9
2014 Plan [Member] | Employee Severance [Member] | MENA/ Asia Pacific [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			4
2014 Plan [Member] | Employee Severance [Member] | Europe/ SSA/ Russia [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			15
2014 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			19
2014 Plan [Member] | Employee Severance [Member] | Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			3
2014 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Segment Reporting Information [Line Items]
Severance, asset impairment and other restructuring charges			$ 16

[1] For the three months ended March 31, 2015, we recognized restructuring charges of $41 million: $8 million in North America, $6 million in MENA/Asia Pacific, $7 million in Europe/SSA/Russia, $12 million in Latin America, $5 million in Land Drilling Rigs and $3 million in Corporate and Research and Development.

[2] For the three months ended March 31, 2014, we recognized restructuring charges of $70 million: $9 million in North America, $4 million in MENA/Asia Pacific, $19 million in Europe/SSA/Russia, $19 million in Latin America, $3 million in Land Drilling Rigs and $16 million in Corporate and Research and Development.