Business Combinations, Goodwill by Segment (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
BUSINESS COMBINATIONS, GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
Finite-Lived Intangible Assets, Net	$ 829.7
Identifiable intangibles with indefinite useful lives	49.8
Goodwill [Line Items]
Servicing Asset at Amortized Cost, Other than Temporary Impairments	7.8	$ 3.1
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	5.8
Goodwill, Translation Adjustments	(19.5)
Goodwill	4,597.9
Goodwill	4,611.6
Markets Advisory
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	0.0
Goodwill, Translation Adjustments	(7.9)
Goodwill	1,775.0
Goodwill	1,782.9
Capital Markets
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	0.8
Goodwill, Translation Adjustments	(8.8)
Goodwill	1,975.9
Goodwill	1,983.9
Work Dynamics
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	4.6
Goodwill, Translation Adjustments	(2.4)
Goodwill	542.1
Goodwill	539.9
JLL Technologies
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	0.4
Goodwill, Translation Adjustments	0.0
Goodwill	247.9
Goodwill	247.5
Investment Management [Member]
Goodwill [Roll Forward]
Goodwill Additions, net of adjustments	0.0
Goodwill, Translation Adjustments	(0.4)
Goodwill	57.0
Goodwill	$ 57.4

-- None. No documentation exists for this element. --

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- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation. Also includes purchase price allocation adjustment for allocations not yet complete at the prior year end.

+ References

No definition available.

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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- Definition

Amount of other-than-temporary impairment (OTTI) applied to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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