Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

Revenue Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2024	Jan. 01, 2024	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	$ 2,187.1		$ 2,386.1
Accounts receivable, net of allowance of $37.0 and $46.4, respectively	5,649.7		5,768.8
Accounts receivable, billable to clients	2,088.4		2,229.2
Assets held for sale	51.4		21.9
Other current assets	77.0		128.6
Assets, Current	10,606.0		10,950.4
Property, Plant and Equipment, Net	566.8		636.7
Goodwill	4,689.4	$ 5,080.9	5,080.9	$ 5,050.6	$ 5,050.6
Other intangible assets	659.9		743.6
Other non-current assets	516.7		428.1
Assets	18,325.8		19,267.3
Accounts Payable, Current	8,286.1		8,355.0
Accrued Liabilities, Current	661.6		705.8
Contract liabilities	509.0		684.7
Short-term borrowings	40.5		34.2
Current portion of long-term debt	0.1		250.1
Liabilities held for sale	23.5		48.5
Liabilities, Current	9,758.0		10,330.9
Long-term debt	2,920.5		2,917.5
Deferred compensation	202.3		223.6
Other non-current liabilities	478.6		532.4
Liabilities	14,415.7		15,221.2
Redeemable noncontrolling interests	45.6		42.3		38.3	$ 15.6
STOCKHOLDERS' EQUITY:
Common stock, $0.10 par value, shares authorized: 800.0 shares issued: 2024 - 372.4; 2023 - 383.0 shares outstanding: 2024 - 372.4; 2023 - 378.7	37.2		38.3
Additional Paid in Capital	432.6		728.5
Retained Earnings (Accumulated Deficit)	4,440.2		4,254.5
Accumulated other comprehensive loss, net of tax	(1,112.6)		(946.2)		(993.7)
Equity, Attributable to Parent	3,797.4		3,942.6
Equity, Attributable to Noncontrolling Interest	67.1		61.2
Equity, Including Portion Attributable to Noncontrolling Interest	3,864.5		4,003.8		$ 3,672.7	$ 3,589.2
Liabilities and Equity	$ 18,325.8		$ 19,267.3