Dispositions and Other Transactions - Summary of Assets Held for Sale (Details) - Anadarko's Africa Assets - Discontinued Operations, Disposed of by Sale - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	$ 378	$ 289
Property, plant and equipment, net	5,235	5,481
Long-term receivables and other assets, net	119	256
Assets held for sale	5,732	6,026
Current liabilities	399	452
Long-term debt, net - finance leases	183	185
Deferred income taxes	1,096	1,112
Asset retirement obligations	183	181
Other	30	80
Liabilities of assets held for sale	1,891	2,010
Net assets held for sale	$ 3,841	$ 4,016