Components of Deferred Tax Assets / (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Liabilities, Property and Equipment	$ (15,581)	$ (15,346)
Deferred Tax Liabilities, Operating Lease Right-Of-Use-Assets	(269)	(243)
Deferred Tax Liabilities, Other	(822)	(806)
Deferred Tax Liabilities, Gross	(16,672)	(16,395)
Deferred Tax Assets, Operating Lease Liabilities	266	239
Deferred Tax Assets, Compensation and Benefits	170	168
Deferred Tax Assets, Casualty and environmental	97	96
Deferred Tax Assets, Other	154	196
Total Deferred Tax Assets	687	699
Deferred Tax Liabilities, Net	$ (15,985)	$ (15,696)