Restructuring Liability (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2017	$ 143.6
Restructuring charges	25.7
Cash paid	(33.6)
Foreign currency translation adjustments and other	1.9
Restructuring liability as of March 31, 2017	137.6
Current portion		$ 98.7
Noncurrent portion		38.9
Total	143.6	137.6
Employee severance and termination costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2017	77.6
Restructuring charges	23.0
Cash paid	(31.4)
Foreign currency translation adjustments and other	1.2
Restructuring liability as of March 31, 2017	70.4
Current portion		65.6
Noncurrent portion		4.8
Total	77.6	70.4
Office closures [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2017	7.3
Restructuring charges	0.2
Cash paid	(0.6)
Foreign currency translation adjustments and other	(0.1)
Restructuring liability as of March 31, 2017	6.8
Current portion		2.0
Noncurrent portion		4.8
Total	7.3	6.8
Contract termination and other [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2017	58.7
Restructuring charges	2.5
Cash paid	(1.6)
Foreign currency translation adjustments and other	0.8
Restructuring liability as of March 31, 2017	60.4
Current portion		31.1
Noncurrent portion		29.3
Total	58.7	$ 60.4
Latin America and the Caribbean (CWC) [Member] | Employee severance and termination costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	9.1
Germany | Employee severance and termination costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	9.0
European Operations Division Central and Other [Member] | Employee severance and termination costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	$ 3.5