Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Summary of Significant Accounting Policies

Accounts Receivable, Allowance for Credit Loss [Table Text Block]

The following table reflects the activity in our allowance for doubtful accounts of trade receivables for the year ended December 31 (in millions):

	2022		2021
Balance as of January 1	$	25	$	33
Additions charged to expense		55		35
Accounts written-off, net of recoveries		(49)		(36)
Acquisitions, divestitures and other, net		(5)		(7)
Balance as of December 31	$	26	$	25

Summary of the impact of revisions in risk-free discount rate

	2022			2021			2020
Increase (decrease) in operating expenses	$	(14)		$	(4)		$	8
Risk-free discount rate applied to environmental remediation liabilities and recovery assets		3.75	%		1.50	%		1.00	%

Schedule of estimated useful lives

The estimated useful lives for significant property and equipment categories are as follows (in years):

	Useful Lives
Vehicles — excluding rail haul cars	3 to 10
Vehicles — rail haul cars	10 to 30
Machinery and equipment — including containers	3 to 30
Buildings and improvements	5 to 40
Furniture, fixtures and office equipment	3 to 10

Summary of investments in unconsolidated entities

	2022		2021
Equity method investments	$	460	$	335
Investments without readily determinable fair values		62		48
Redeemable preferred stock		56		49
Investments in unconsolidated entities	$	578	$	432

Schedule of Supplemental Cash Flow Information

The following table shows supplemental cash flow information for the year ended December 31 (in millions):

	2022		2021		2020
Interest, net of capitalized interest	$	348	$	387	$	461
Income taxes (a)		736		370		422

(a) The increase in income taxes paid in 2022 is primarily due to the increase in pre-tax book income during 2022 and a deposit of approximately $103 million made to the Internal Revenue Service (“IRS”) in the fourth quarter of 2022 related to a disputed tax matter for which we expect to seek a refund. See Note 8 for further discussion.