Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Leases
ROU asset	$ 195.0		$ 195.0		$ 199.7
Balance sheet location of ROU asset	us-gaap:OtherAssets		us-gaap:OtherAssets		us-gaap:OtherAssets
Lease liability	$ 234.9		$ 234.9		$ 242.3
Balance sheet location of lease liability	us-gaap:OtherLiabilities		us-gaap:OtherLiabilities		us-gaap:OtherLiabilities
Operating lease costs	$ 12.8	$ 14.3	$ 26.0	$ 29.3
Lessee, Operating Lease, Existence of Option to Extend [true false]			true
Minimum
Leases
Lease terms	1 year		1 year
Maximum
Leases
Lease terms	11 years		11 years
Lease extension terms	10 years		10 years