Income Taxes Narrative (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($) country	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) country	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Income Tax Contingency [Line Items]
Income Tax Expense (Benefit)									$ (145)	$ 284	$ 144
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									(2,096)	(255)	(170)
Long-Lived Asset Impairments and Other Related Charges									768	495	0
Severance and Restructuring Charges				$ 59				$ 96	232	331	0
Litigation Charges									116	0	153
Currency Devaluation and Related Charges									85	245	100
Goodwill and Equity Investment Impairment									25	161	0
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount									265	0	0
Goodwill, Impairment Loss										66
Impairment of Long-Lived Assets Held-for-use					$ (352)				(638)	(495)	0
Gain (Loss) on Disposition of Business					311				(6)	349	24
Gain (Loss) on Sale of Interest in Projects											(299)
Bad Debt Expense	$ 31								48	27	102
Undistributed Earnings of Foreign Subsidiaries	103								103
Operating Loss Carryforwards	3,500								3,500
Tax Credit Carryforward, Amount	102								102
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense									4	53	21
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 50				58				$ 50	58	121
Number of Countries in which Entity Operates | country	100								100
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 10								$ 10
VENEZUELA
Income Tax Contingency [Line Items]
Bad Debt Expense											98
UNITED STATES
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	867								867
Tax Credit Carryforward, Amount	82								82
IRAQ
Income Tax Contingency [Line Items]
Loss on Contracts	82	$ 44	$ 69		34	$ 10	$ 2	$ 26	153	72	232
Venezuelan Bolivar
Income Tax Contingency [Line Items]
Currency Devaluation and Related Charges					$ 245				26
Currency devaluation expense										245	100
Foreign Tax Credit Carryforward [Member] | UNITED STATES
Income Tax Contingency [Line Items]
Tax Credit Carryforward, Amount	52								52
Research Tax Credit Carryforward [Member] | UNITED STATES
Income Tax Contingency [Line Items]
Tax Credit Carryforward, Amount	$ 30								30
Goodwill [Member]
Income Tax Contingency [Line Items]
Goodwill, Impairment Loss										161
Drilling Rigs [Member]
Income Tax Contingency [Line Items]
Severance and Restructuring Charges										9
Goodwill, Impairment Loss										$ 40
Impairment of Long-Lived Assets Held-for-use									$ (255)
Bad Debt Expense											$ 26