Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accrued Liabilities [Abstract]
Salaries, benefits and related expenses	$ 494.9	$ 441.7
Office and related expenses	52.2	53.2
Acquisition obligations	65.7	42.0
Interest	43.6	16.4
Other	150.5	121.4
Total accrued liabilities	$ 806.9	$ 674.7

Acquisition Obligations, current

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- Definition

Current office and related expenses such as deferred rent expense and lease costs.

+ References

No definition available.

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- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- References

No definition available.

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- Definition

Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

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- Definition

Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

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- Definition

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

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