Restructuring Charges (Restructuring Liability) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 59	$ 280	$ 232	$ 331
Severance and Other Restructuring Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				331
Restructuring and Related Cost, Incurred Cost		240
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period		51
Cash Payments		(198)		(106)
Other		7
Accrued balance at end of period		86	51
Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member] | North America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		27
Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member] | Middle East/North Africa/Asia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		12
Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		16
Severance and Other Restructuring Liabilities [Member] | Operating Segments [Member] | Latin America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
Severance and Other Restructuring Liabilities [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		30
Severance and Other Restructuring Liabilities [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		55
Severance and Other Restructuring Liabilities [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		1
2014 & 2015 Plan [Member] | Operating Segments [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				76
2014 & 2015 Plan [Member] | Operating Segments [Member] | Middle East/North Africa/Asia [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				133
2014 & 2015 Plan [Member] | Operating Segments [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				35
2014 & 2015 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				48
2014 & 2015 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				30
2014 & 2015 Plan [Member] | Drilling Rigs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				$ 9
2014 & 2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		0
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period		37
Cash Payments		(28)
Other		6
Accrued balance at end of period		3	37
2014 & 2015 Plan [Member] | Employee Severance [Member] | North America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		2
2014 & 2015 Plan [Member] | Employee Severance [Member] | Middle East/North Africa/Asia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		1
2014 & 2015 Plan [Member] | Employee Severance [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2014 & 2015 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2014 & 2015 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2014 & 2015 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		3
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 Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		0
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period		14
Cash Payments		(5)
Other		0
Accrued balance at end of period		9	14
2014 & 2015 Plan [Member] | Other Restructuring [Member] | North America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		1
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Middle East/North Africa/Asia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		1
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		7
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Latin America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
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		9
2014 & 2015 Plan [Member] | Other Restructuring [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		280
2016 Plan [Member] | Operating Segments [Member] | North America [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		96
2016 Plan [Member] | Operating Segments [Member] | Middle East/North Africa/Asia [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		33
2016 Plan [Member] | Operating Segments [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		36
2016 Plan [Member] | Operating Segments [Member] | Latin America [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		56
2016 Plan [Member] | Corporate and Research and Development [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		52
2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		196
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period		0
Cash Payments		(147)
Other		(3)
Accrued balance at end of period		52	0
2016 Plan [Member] | Employee Severance [Member] | North America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		8
2016 Plan [Member] | Employee Severance [Member] | Middle East/North Africa/Asia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		6
2016 Plan [Member] | Employee Severance [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		7
2016 Plan [Member] | Employee Severance [Member] | Latin America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2016 Plan [Member] | Employee Severance [Member] | Corporate and Research and Development [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		30
2016 Plan [Member] | Employee Severance [Member] | Core Regional Segments [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		21
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 Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		44
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period		0
Cash Payments		(18)
Other		4
Accrued balance at end of period		22	$ 0
2016 Plan [Member] | Other Restructuring [Member] | North America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		16
2016 Plan [Member] | Other Restructuring [Member] | Middle East/North Africa/Asia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		4
2016 Plan [Member] | Other Restructuring [Member] | Europe/Sub-Sahara Africa/Russia [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		2
2016 Plan [Member] | Other Restructuring [Member] | Latin America [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
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		22
2016 Plan [Member] | Other Restructuring [Member] | Drilling Rigs [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period		0
2016 Plan [Member] | Severance and Other Restructuring Liabilities [Member] | Core Regional Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		$ 221