Property, Plant and Equipment (PP&E) (Summary of Property, Plant And Equipment) (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Property, Plant, and Equipment [Line Items]
Gross PP&E	$ 73,971		$ 73,971		$ 71,009
Accumulated Depreciation	35,678		35,678		33,612
Net PP&E	38,293		38,293		37,397
Depreciation	758	$ 769	2,250	$ 2,220
Operating Segments \| Refining & Marketing
Property, Plant, and Equipment [Line Items]
Gross PP&E	35,169		35,169		34,372
Accumulated Depreciation	21,438		21,438		20,462
Net PP&E	13,731		13,731		13,910
Operating Segments \| Midstream
Property, Plant, and Equipment [Line Items]
Gross PP&E	36,239		36,239		34,057
Accumulated Depreciation	12,677		12,677		11,690
Net PP&E	23,562		23,562		22,367
Operating Segments \| Renewable Diesel
Property, Plant, and Equipment [Line Items]
Gross PP&E	970		970		970
Accumulated Depreciation	441		441		396
Net PP&E	529		529		574
Corporate
Property, Plant, and Equipment [Line Items]
Gross PP&E	1,593		1,593		1,610
Accumulated Depreciation	1,122		1,122		1,064
Net PP&E	$ 471		$ 471		$ 546

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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