Fixed Assets - Summary of Fixed Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment Useful Life And Values [Abstract]
Office equipment	$ 33.0	$ 32.6
Furniture and fixtures	138.3	126.0
Leasehold improvements	166.0	150.2
Computer equipment	214.2	176.3
Land and buildings - corporate headquarters	145.1	144.9
Software	452.2	392.3
Other	16.7	19.0
Work in process	14.1	18.0
Gross fixed assets	1,179.6	1,059.3
Accumulated depreciation	(728.9)	(591.9)
Net fixed assets	$ 450.7	$ 467.4

Computer Equipment, Gross

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- Definition

Land and buildings gross.

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Property Plant and Equipment Useful Life and Values [Abstract]

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No definition available.

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated amortization of capitalized costs for computer software, including but not limited to, acquired and internally developed computer software.

+ References

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depreciation of equipment commonly used in offices and stores that have no permanent connection to the structure of a building or utilities. Examples include, but are not limited to, desks, chairs, tables, and bookcases.

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Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale.

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