Cash And Cash Equivalents Net Change in Operating Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Mar. 31, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Accounts receivable				$ 1,307	$ (353)
Accounts receivable from related companies				(258)	(36)
Inventories				(298)	(7)
Other current assets				108	14
Other non-current assets, net				(26)	(151)
Accounts payable				(1,354)	25
Accounts payable to related companies				370	(37)
Accrued and other current liabilities				127	129
Other non-current liabilities				(5)	(103)
Derivative assets and liabilities, net				123	307
Net change in operating assets and liabilities, net of effects of acquisitions	$ 444	$ (1)	$ (234)	$ (94)	$ 212	[1]

[1] *As adjusted. See Note 1.