Additional Details Related to Certain Balance Sheet Captions (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other current assets:
Prepaid taxes	$ 55.5	$ 94.9
Prepaid expenses	95.7	91.7
Other	43.2	47.6
Total other current assets	233.6	250.1
Other assets
Investments in joint ventures	100.4	99.1
Deposits for real-estate leases	12.2	12.3
Indemnification assets related to acquisitions	16.8	17.0
Mutual funds and fixed deposits	44.3	22.1
Other	15.0	9.4
Total other assets	258.0	159.9
Accounts payable and accrued liabilities
Salaries and benefits	136.6	129.6
Incentive compensation	51.0	246.7
Customer credits, advanced payments and advanced billings	27.4	22.2
Self-insurance reserves	9.9	8.1
Dividends	4.8	6.2
Professional service fees	49.9	47.1
Interest accrued on debt	30.2	73.9
Accounts payable	32.0	21.8
Income taxes	86.7	79.2
Pension and other post retirement employee benefits	5.9	5.9
Accrued royalties	19.6	26.4
Other	78.6	83.2
Total accounts payable and accrued liabilities	532.6	750.3
Other liabilities
Pension and other post retirement employee benefits	256.0	244.5
Deferred rent-non-current portion	101.7	103.1
Interest accrued on UTPs	52.8	54.7
Other tax matters	1.3	1.3
Other	34.4	28.2
Income tax liability - non-current	108.0	232.2
Total other liabilities	554.2	664.0
Other Current Assets [Member]
Other current assets:
Capitalized costs to obtain and fulfill sales contracts	39.2	$ 15.9
Other Assets [Member]
Other current assets:
Capitalized costs to obtain and fulfill sales contracts	$ 69.3