Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Total Gross Assets & Liabilities [Domain]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	$ 1,653	$ 635
Advances to/receivables from equity companies	8,711	8,670
Other long-term financial assets	2,046	2,119
Derivative liabilities	1,836	638
Long-term debt	49,276	25,789
Long-term obligations to equity companies	3,766	4,245
Other long-term financial liabilities	1,066	1,042
Net Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	165	102
Advances to/receivables from equity companies	8,759	8,542
Other long-term financial assets	2,183	2,163
Derivative liabilities	88	70
Long-term debt	45,314	24,672
Long-term obligations to equity companies	3,831	3,988
Other long-term financial liabilities	1,072	1,058
Effect Of Counterparty Netting [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	(1,423)	(463)
Derivative liabilities	(1,423)	(463)
Effect Of Collateral Netting [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	(65)	(70)
Derivative liabilities	(325)	(105)
Difference In Carrying Value And Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	48	(128)
Other long-term financial assets	137	44
Long-term debt	(3,962)	(1,117)
Long-term obligations to equity companies	65	(257)
Other long-term financial liabilities	6	16
Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	1,488	533
Other long-term financial assets	1,157	1,145
Derivative liabilities	1,748	568
Long-term debt	49,106	25,652
Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets	165	102
Advances to/receivables from equity companies	1,916	1,941
Derivative liabilities	88	70
Long-term debt	166	134
Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Advances to/receivables from equity companies	6,795	6,729
Other long-term financial assets	889	974
Long-term debt	4	3
Long-term obligations to equity companies	3,766	4,245
Other long-term financial liabilities	$ 1,066	$ 1,042