Commitments and Contingencies - Narrative (Details)	1 Months Ended		12 Months Ended
	Mar. 31, 2016 mi	May 31, 2007 entity	Dec. 31, 2017 USD ($) mi	Dec. 30, 2016 USD ($)
Operating Leased Assets [Line Items]
Maximum lease term (up to)			30 years
Locomotive fleet covered by maintenance program (as a percent)			50.00%
Estimated obligation under maintenance program			$ 4,217,000,000
Non-catastrophic property deductible			25,000,000
Casualty and catastrophic property deductible			$ 50,000,000
Fuel Surcharge Antitrust Litigation
Operating Leased Assets [Line Items]
Number of other U.S.-based entities mentioned in class action lawsuit | entity		3
Environmental Litigation
Operating Leased Assets [Line Items]
Number of miles pertaining to Passaic River tidal reach required to be studied by EPA | mi			17
Number of miles under study | mi	8
Years to clean up site			10 years
Minimum | Pending Litigation
Operating Leased Assets [Line Items]
Range of possible loss from legal proceedings			$ 2,000,000
Maximum | Pending Litigation
Operating Leased Assets [Line Items]
Range of possible loss from legal proceedings			117,000,000
Locomotive Maintenance Payments
Operating Leased Assets [Line Items]
Estimated obligation under maintenance program			$ 3,715,000,000	$ 4,900,000,000