Restructuring Charges (Restructuring Liability) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Severance and Other Restructuring Liabilities
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	$ 86
Restructuring Charges	128
Cash Payments	(129)
Other	(27)
Accrued balance at end of period	58
Severance and Other Restructuring Liabilities | Corporate and Research and Development
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	9
Severance and Other Restructuring Liabilities | Core Regional Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	49
Severance and Other Restructuring Liabilities | Land Drilling Rigs
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2016 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	52
Restructuring Charges	71
Cash Payments	(104)
Other	(3)
Accrued balance at end of period	16
2016 Plan | Employee Severance | Corporate and Research and Development
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	9
2016 Plan | Employee Severance | Core Regional Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	7
2016 Plan | Employee Severance | Land Drilling Rigs
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2016 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	22
Restructuring Charges	57
Cash Payments	(21)
Other	(21)
Accrued balance at end of period	37
2016 Plan | Other Restructuring | Corporate and Research and Development
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2016 Plan | Other Restructuring | Core Regional Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	37
2016 Plan | Other Restructuring | Land Drilling Rigs
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	3
Restructuring Charges	0
Cash Payments	(3)
Other	0
Accrued balance at end of period	0
2014 & 2015 Plan | Employee Severance | Corporate and Research and Development
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan | Employee Severance | Core Regional Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan | Employee Severance | Land Drilling Rigs
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	9
Restructuring Charges	0
Cash Payments	(1)
Other	(3)
Accrued balance at end of period	5
2014 & 2015 Plan | Other Restructuring | Corporate and Research and Development
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
2014 & 2015 Plan | Other Restructuring | Core Regional Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
2014 & 2015 Plan | Other Restructuring | Land Drilling Rigs
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
North America | Severance and Other Restructuring Liabilities | Operating Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	18
North America | 2016 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
North America | 2016 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	17
North America | 2014 & 2015 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
North America | 2014 & 2015 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Middle East, North Africa, and Asia | Severance and Other Restructuring Liabilities | Operating Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	15
Middle East, North Africa, and Asia | 2016 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	4
Middle East, North Africa, and Asia | 2016 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	11
Middle East, North Africa, and Asia | 2014 & 2015 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Middle East, North Africa, and Asia | 2014 & 2015 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Europe, Sub-Sahara Africa, Russia | Severance and Other Restructuring Liabilities | Operating Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	16
Europe, Sub-Sahara Africa, Russia | 2016 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	2
Europe, Sub-Sahara Africa, Russia | 2016 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	9
Europe, Sub-Sahara Africa, Russia | 2014 & 2015 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Europe, Sub-Sahara Africa, Russia | 2014 & 2015 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	5
Latin America | Severance and Other Restructuring Liabilities | Operating Segments
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America | 2016 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America | 2016 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America | 2014 & 2015 Plan | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Latin America | 2014 & 2015 Plan | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	$ 0