Restructuring Charges 2020 Plan Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	$ 44.6	$ 2.1	$ 44.6	$ 22.0
Lease impairment costs	65.7	0.0	65.7	11.9
Other restructuring costs	2.3	0.0	2.3	0.0
Restructuring charges	112.6	$ 2.1	112.6	$ 33.9
Restructuring Reserve	33.8		33.8
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	33.8		33.8
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
Non-cash Items [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	0.7
Lease impairment costs	65.7
Other restructuring costs	1.2
Restructuring charges	67.6
Cash Payments [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	10.1
Lease impairment costs	0.0
Other restructuring costs	1.1
Restructuring charges	$ 11.2