Commitments and Contingencies (Details)		1 Months Ended		3 Months Ended
	Jun. 30, 2018 defendant	Mar. 31, 2016 party mi	May 31, 2007 claim entity	Mar. 31, 2021 USD ($) mi	Mar. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Casualty and catastrophic property deductible					$ 100,000,000
Casualty and non catastrophic property deductible					$ 75,000,000
Pending Litigation | Fuel Surcharge Antitrust Litigation
Loss Contingencies [Line Items]
Class action lawsuits filed against U.S.-based Class I railroads, excluding CSXT (number of entities) | entity			3
Number of consolidated class action lawsuits | claim			1
Pending Litigation | Environmental
Loss Contingencies [Line Items]
Number of miles pertaining to Passaic River tidal reach required to be studied by EPA | mi				17
Number of miles subject to remediation | mi		8
Number of parties participating in allocation process under study | party		80
Number of parties | defendant	110
Minimum | Pending Litigation
Loss Contingencies [Line Items]
Possible loss for certain legal proceedings				$ 1,000,000
Maximum | Pending Litigation
Loss Contingencies [Line Items]
Possible loss for certain legal proceedings				20,000,000
Total Casualty
Loss Contingencies [Line Items]
Self-insured retention amount, per occurrence (up to)				$ 75,000,000