Schedule of Consolidated VIEs, Carrying Amounts of Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Variable Interest Entity [Line Items]
Cash and cash equivalents (variable interest entities restricted - 2021: $36; 2020: $26)	$ 3,491	$ 5,104	$ 3,724
Other current assets	803	889
Net property (variable interest entities restricted - 2021: $204; 2020: $232)	19,864	20,239
Deferred charges and other assets	1,354	1,249
Total Assets	61,768	61,470
Accrued and other current liabilities	3,494	3,790
Long-Term Debt (variable interest entities nonrecourse - 2021: $5; 2020: $6)	15,093	16,491
Other noncurrent obligations	6,428	6,279
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents (variable interest entities restricted - 2021: $36; 2020: $26)	36	26
Other current assets	39	44
Net property (variable interest entities restricted - 2021: $204; 2020: $232)	204	232
Deferred charges and other assets	16	17
Total Assets	295	319
Accrued and other current liabilities	57	73
Long-Term Debt (variable interest entities nonrecourse - 2021: $5; 2020: $6)	5	6
Other noncurrent obligations	16	18
Total Liabilities	$ 78	$ 97