Restructuring Charges 2020 Plan Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Severance and termination costs	$ 17.9	$ 0.0	$ 62.5	$ 22.0
Lease impairment costs	26.6	0.0	92.3	11.9
Other restructuring costs	2.8	0.0	5.1	0.0
Restructuring charges	47.3	$ 0.0	159.9	$ 33.9
Restructuring Reserve	27.5		27.5
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	27.5		27.5
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			1.0
Lease impairment costs			92.3
Other restructuring costs			2.4
Restructuring charges			95.7
Cash Payments [Member]
Restructuring Cost and Reserve [Line Items]
Severance and termination costs			34.0
Lease impairment costs			0.0
Other restructuring costs			2.7
Restructuring charges			$ 36.7