Financial Instruments (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Total Gross Assets & Liabilities [Domain]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	[1]	$ 297
Advances to/receivables from equity companies	[2],[3]	8,393
Other long-term financial assets	[4]	1,822
Derivative liabilities	[5]	151
Long-term debt	[6]	19,150
Long-term obligations to equity companies	[2]	4,330
Other long-term financial liabilities	[7]	1,046
Net Carrying Value Presented on the Balance Sheet [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	[2],[3]	8,608
Other long-term financial assets	[4]	1,934
Long-term debt	[6]	19,235
Long-term obligations to equity companies	[2]	4,382
Other long-term financial liabilities	[7]	1,043
Long-term debt			$ 23,700
Effect Of Counterparty Netting [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	[1]	(151)
Derivative liabilities	[5]	(151)
Effect Of Collateral Netting [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	[1]	(146)
Difference In Carrying Value And Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	[2],[3]	215
Other long-term financial assets	[4]	112
Long-term debt	[6]	85
Long-term obligations to equity companies	[2]	52
Other long-term financial liabilities	[7]	(3)
Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	[1]	297
Other long-term financial assets	[4]	848
Derivative liabilities	[5]	151
Long-term debt	[6]	19,029
Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	[2],[3]	2,100
Long-term debt	[6]	117
Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	[2],[3]	6,293
Other long-term financial assets	[4]	974
Long-term debt	[6]	4
Long-term obligations to equity companies	[2]	4,330
Other long-term financial liabilities	[7]	$ 1,046

[1] Included in the Balance Sheet line: Notes and accounts receivable, less estimated doubtful amounts

[2] Advances to/receivables from equity companies and long-term obligations to equity companies are mainly designated as hierarchy level 3 inputs. The fair value is calculated by discounting the remaining obligations by a rate consistent with the credit quality and industry of the equity company.

[3] Included in the Balance Sheet line: Investments, advances and long-term receivables

[4] Included in the Balance Sheet lines: Investments, advances and long-term receivables and Other assets, including intangibles, net

[5] Included in the Balance Sheet line: Accounts payable and accrued liabilities

[6] Excluding capitalized lease obligations

[7] Included in the Balance Sheet line: Other long-term obligations