Business Combinations - Narrative (Details) $ in Millions			3 Months Ended		6 Months Ended	19 Months Ended
	Jun. 01, 2022 USD ($) mi	Jul. 01, 2021 USD ($) terminalAndFacility	Jun. 30, 2022 USD ($) mi	Dec. 31, 2020 USD ($)	Jun. 30, 2022 USD ($) mi	Jun. 30, 2022 USD ($) mi	Dec. 31, 2021 USD ($)
Business Acquisition [Line Items]
Number of rail route miles | mi			20,000		20,000	20,000
Goodwill			$ 377		$ 377	$ 377	$ 276
Intangible assets acquired					$ 10
Pan Am Systems, Inc.
Business Acquisition [Line Items]
Business combination, closing price	$ 601
Business combination, common stock issued	422
Purchase price in cash paid for acquisition	179
Payments for deposits				$ 30
Properties acquired	536
Acquisition related costs			$ 18			$ 29
Goodwill	$ 84
Pan Am Systems, Inc. | Pan Am Systems, Inc.
Business Acquisition [Line Items]
Number of rail route miles | mi	1,200
Number of partial interests in rail route miles (more than) | mi	600
Quality Carriers, Inc.
Business Acquisition [Line Items]
Purchase price in cash paid for acquisition		$ 541
Cash and cash equivalents acquired		3
Goodwill		213
Intangible assets acquired		180
Quality Carriers, Inc. | Customer Relationships
Business Acquisition [Line Items]
Intangible assets acquired		$ 150
Amortization period of intangible assets acquired		20 years
Quality Carriers, Inc. | Trade Names
Business Acquisition [Line Items]
Intangible assets acquired		$ 30
Amortization period of intangible assets acquired		15 years
Quality Carriers, Inc. | Quality Carriers, Inc. | United States, Canada and Mexico
Business Acquisition [Line Items]
Number of terminals and facilities (over) | terminalAndFacility		100