Segment Information Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Net Operating Revenues	$ 2,012	$ 2,237	$ 2,390	$ 2,794	$ 3,727	$ 3,877	$ 3,711	$ 3,596	$ 9,433		$ 14,911		$ 15,263
Long-lived Assets	5,858				7,365				5,858		7,365
Operating Income (Loss)									(1,546)		505		523
Depreciation and Amortization									1,200		1,371		1,402
Capital Expenditures for Property, Plant and Equipment									(682)		(1,450)		(1,575)
Research and Development Expense									(231)		(290)		(265)
Long-Lived Asset Impairments and Other Related Charges									768		495		0
Goodwill Impairment											66
Equity Investment Impairment			$ (25)
Severance and Restructuring Charges				$ (59)				$ (96)	(232)		(331)		0
Loss Contingency Accrual, Provision									0		0		(153)
Gain (Loss) on Disposition of Business					311				(6)		349		24
Total Assets	14,787				18,889				14,787		18,889
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									9,433		14,911		15,263
Operating Income (Loss)									78		1,723		1,318
Depreciation and Amortization									1,176		1,348		1,382
Capital Expenditures for Property, Plant and Equipment									(663)		(1,388)		(1,512)
Corporate and Research and Development [Member]
Segment Reporting Information [Line Items]
Depreciation and Amortization									24		23		20
Capital Expenditures for Property, Plant and Equipment									(19)		(62)		(63)
Research and Development Expense									(425)		(468)		(466)
Severance and Restructuring Charges											(30)
Total Assets	472				346				472		346
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Long-Lived Asset Impairments and Other Related Charges									768	[1]	495
Goodwill Impairment											161
Equity Investment Impairment									(25)
Severance and Restructuring Charges									(232)	[2]	(331)	[3]
Loss Contingency Accrual, Provision									(116)				(153)
Gain (Loss) on Disposition of Business									(6)		349		24
Other Nonoperating Expense									(52)	[4]	112	[5]	200
Core Regional Segments [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									8,720		13,669		13,718
Operating Income (Loss)									91		1,826		1,351
Depreciation and Amortization									1,066		1,169		1,169
Capital Expenditures for Property, Plant and Equipment									(595)		(1,230)		(1,185)
Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Goodwill Impairment											40
Severance and Restructuring Charges											(9)
Drilling Rigs [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									713		1,242		1,545
Operating Income (Loss)									(13)		(103)		(33)
Depreciation and Amortization									110		179		213
Capital Expenditures for Property, Plant and Equipment									(68)		(158)		(327)
Total Assets	1,516				1,907				1,516		1,907
North America [Member]
Segment Reporting Information [Line Items]
Severance and Restructuring Charges											(76)
North America [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									3,494		6,852		6,390
Operating Income (Loss)									(308)		1,005		827
Depreciation and Amortization									362		430		424
Capital Expenditures for Property, Plant and Equipment									(161)		(454)		(434)
Total Assets	5,100				7,297				5,100		7,297
Middle East/North Africa/Asia [Member]
Segment Reporting Information [Line Items]
Severance and Restructuring Charges											(133)
Middle East/North Africa/Asia [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									1,947		2,406		2,746
Operating Income (Loss)									(28)		115		(62)
Depreciation and Amortization									254		280		284
Capital Expenditures for Property, Plant and Equipment									(75)		(183)		(278)
Total Assets	2,536				3,022				2,536		3,022
Europe/Sub-Sahara Africa/Russia [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									1,613		2,584		2,693
Long-lived Assets	862				1,158				862		1,158
Severance and Restructuring Charges											(35)
Europe/Sub-Sahara Africa/Russia [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									1,533		2,129		1,947
Operating Income (Loss)									173		367		266
Depreciation and Amortization									201		218		207
Capital Expenditures for Property, Plant and Equipment									(132)		(282)		(228)
Total Assets	2,480				3,106				2,480		3,106
Latin America [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									1,782		2,381		2,835
Long-lived Assets	1,143				1,226				1,143		1,226
Severance and Restructuring Charges											(48)
Latin America [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Operating Revenues									1,746		2,282		2,635
Operating Income (Loss)									254		339		320
Depreciation and Amortization									249		241		254
Capital Expenditures for Property, Plant and Equipment									(227)		(311)		$ (245)
Total Assets	$ 2,683				$ 3,211				$ 2,683		$ 3,211

[1] Includes asset impairment charges of $638 million, supply agreement charges related to a non-core business divestiture of $67 million

[2] We recognized 2015 Plan severance and restructuring charges of $232 million: $52 million in North America, $56 million in MENA/Asia Pacific, $56 million in Europe/SSA/Russia, $40 million in Latin America, $12 million in Land Drilling Rigs and $16 million in Corporate and Research and Development.

[3] We recognized 2014 and 2015 Plan severance and restructuring charges of $331 million: $76 million in North America, $133 million in MENA/Asia Pacific, $35 million in Europe/SSA/Russia, $48 million in Latin America, $9 million in Land Drilling Rigs and $30 million in Corporate and Research and Development.

[4] Includes $17 million in professional and other fees, $11 million in divestiture related charges and facility closures and $24 million in other charges.

[5] We recognized a charge for bad debt expense of $98 million attributable to our reporting segments as follows: $51 million in Latin America, $26 million in Land Drilling Rigs, $10 million for Europe/SSA/Russia, $9 million in MENA/Asia Pacific, and $2 million in North America. During 2013, we recognized a charge for excess and obsolete inventory of $62 million attributable to each reporting segment as follows: $35 million in North America, $13 million in Europe/SSA/Russia, $7 million in MENA/Asia Pacific, $6 million in Latin America and $1 million for Land Drilling Rigs.