Restructuring Charges (Restructuring Liability) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Severance and Other Restructuring Liabilities [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	$ 51
Restructuring Charges	77
Cash Payments	(71)
Other	(3)
Accrued balance at end of period	54
Severance and Other Restructuring Liabilities [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
Severance and Other Restructuring Liabilities [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	48
Severance and Other Restructuring Liabilities [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
2016 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	0
Restructuring Charges	72
Cash Payments	(50)
Other	0
Accrued balance at end of period	22
2016 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	4
2016 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	17
2016 Plan [Member] | Employee Severance [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
2016 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	0
Restructuring Charges	5
Cash Payments	0
Other	0
Accrued balance at end of period	5
2016 Plan [Member] | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2016 Plan [Member] | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
2016 Plan [Member] | Other Restructuring [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	37
Restructuring Charges	0
Cash Payments	(20)
Other	(3)
Accrued balance at end of period	14
2014 & 2015 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
2014 & 2015 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	13
2014 & 2015 Plan [Member] | Employee Severance [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	14
Restructuring Charges	0
Cash Payments	(1)
Other	0
Accrued balance at end of period	13
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	13
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
North America [Member] | Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	17
North America [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	6
North America [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
North America [Member] | 2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
North America [Member] | 2014 & 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
Middle East, North Africa, and Asia [Member] | Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	9
Middle East, North Africa, and Asia [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	2
Middle East, North Africa, and Asia [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Middle East, North Africa, and Asia [Member] | 2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	3
Middle East, North Africa, and Asia [Member] | 2014 & 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	4
Europe, Sub-Sahara Africa, Russia [Member] | Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	22
Europe, Sub-Sahara Africa, Russia [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	9
Europe, Sub-Sahara Africa, Russia [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Europe, Sub-Sahara Africa, Russia [Member] | 2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
Europe, Sub-Sahara Africa, Russia [Member] | 2014 & 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	8
Latin America [Member] | Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America [Member] | 2016 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America [Member] | 2016 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America [Member] | 2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America [Member] | 2014 & 2015 Plan [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	$ 0