Restructuring and Related Activities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) ft² numberOfPeople	Dec. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	$ 0.4	$ 140.4	$ 22.0
Lease Restructuring Cost	6.3	256.0	11.9
Other Restructuring Costs	3.9	17.4	0.0
Restructuring Charges	10.6	413.8	$ 33.9
Restructuring Reserve	9.4	$ 74.6
Restructuring and Related Cost, Number of Positions Eliminated | numberOfPeople		1,520
Restructuring and Related Cost, Number of Positions Eliminated, Inception to Date Percent		3.00%
Area of Real Estate Property | ft²		1,700,000
IAN
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	3.0	$ 317.9
DXTRA
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	9.7	78.8
Non-cash Items [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	0.3	4.5
Lease Restructuring Cost		256.0
Other Restructuring Costs	3.2	5.1
Restructuring Charges	9.8	265.6
Cash Payments [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	65.3	61.3
Lease Restructuring Cost		0.0
Other Restructuring Costs	0.7	12.3
Restructuring Charges	66.0	73.6
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	9.4	74.6
Lease impairment costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.0	0.0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 0.0	$ 0.0