Nature of Operations and Significant Accounting Policies - Narrative (Details) $ in Millions	3 Months Ended				6 Months Ended		21 Months Ended
	Jun. 30, 2023 USD ($) state mi	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2023 USD ($) state mi	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Mar. 26, 2021 property phase
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rail route network, distance | mi	20,000				20,000
Number of states rail network serves | state	26				26
Proceeds from sale of property, plant, and equipment					$ 35	$ 29
Gain (loss) on disposition of property plant equipment	$ 12		$ 129		$ 20	$ 156
Virginia Line Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of property rights for sale | property								3
Number of phases to complete property rights sale transaction | phase								3
Proceeds from sale of property, plant, and equipment		$ 125					$ 525
Gain (loss) on disposition of property plant equipment		$ 122		$ 20			$ 493