Restructuring Activities (Tables)

12 Months Ended

Dec. 31, 2023

Restructuring and Related Activities [Abstract]

Summary of Transformation Initiative Costs

	Year Ended December 31, 2023
	Advisory Services		Global Workplace Solutions		Real Estate Investments		Corporate		Consolidated
Employee separation benefits	$	26	$	32	$	13	$	11	$	82
Lease exit costs	39		1		4		1		45
Professional fees and other	7		19		4		2		32
Subtotal	72		52		21		14		159
Depreciation expense	6		—		3		—		9
Total	$	78	$	52	$	24	$	14	$	168

	Year Ended December 31, 2022
	Advisory Services		Global Workplace Solutions		Real Estate Investments		Corporate		Consolidated
Employee separation benefits	$	33	$	20	$	9	$	19	$	81
Lease exit costs	10		3		—		—		13
Professional fees and other	3		5		3		13		24
Subtotal	46		28		12		32		118
Depreciation expense	5		3		—		—		8
Total	$	51	$	31	$	12	$	32	$	126

Schedule of Liability Balance Associated with major Cash-based Charges

The following table shows ending liability balances associated with major cash-based charges (dollars in millions):

	Employee separation benefits		Professional fees
Balance at January 1, 2022	$	—	$	—
Expense incurred	82		23
Payments made	(45)		(13)
Balance at December 31, 2022	37		10
Expense incurred	82		32
Payments made	(106)		(42)
Balance at December 31, 2023	$	13	$	—