Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Summary of Significant Accounting Policies

Summary of allowance for doubtful accounts

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

	2023		2022
Balance as of January 1	$	26	$	25
Additions charged to expense		53		55
Accounts written-off, net of recoveries		(58)		(49)
Acquisitions, divestitures and other, net		9		(5)
Balance as of December 31	$	30	$	26

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 (a)	3 to 30
Buildings and improvements	5 to 40
Furniture, fixtures and office equipment	3 to 10

(a) Includes recycling and renewable natural gas (“RNG”) facilities as well as containers.

Summary of investments in unconsolidated entities

	2023		2022
Equity method investments	$	538	$	460
Investments without readily determinable fair values		68		62
Redeemable preferred stock		—		56
Investments in unconsolidated entities	$	606	$	578

Schedule of Supplemental Cash Flow Information

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

	2023		2022		2021
Interest, net of capitalized interest	$	447	$	348	$	387
Income taxes (a)		636		736		370

(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.