Operating Segments and Geographic Data - Segment Assets (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Assets
Assets	$ 223,063	$ 237,428
Goodwill	4,416	4,463
United States
Segment Assets
Assets	61,424	64,598
International
Segment Assets
Assets	157,223	168,367
Operating Segments
Segment Assets
Assets	212,921	228,189
Operating Segments | Upstream
Segment Assets
Assets	173,530	186,037
Goodwill	4,416	4,463
Operating Segments | Upstream | United States
Segment Assets
Assets	33,574	35,926
Operating Segments | Upstream | International
Segment Assets
Assets	135,540	145,648
Operating Segments | Downstream
Segment Assets
Assets	39,391	42,152
Operating Segments | Downstream | United States
Segment Assets
Assets	23,335	25,197
Operating Segments | Downstream | International
Segment Assets
Assets	16,056	16,955
All Other
Segment Assets
Assets	10,142	9,239
All Other | United States
Segment Assets
Assets	4,515	3,475
All Other | International
Segment Assets
Assets	$ 5,627	$ 5,764