Leases Leases - Operating future minimum lease payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Operating Leased Assets [Line Items]
2019	$ 83.0
2020	67.2
2021	51.3
2022	39.7
2023	31.8
Later years	130.3
Future minimum payments due	403.3
Facilities
Operating Leased Assets [Line Items]
2019	51.7
2020	46.2
2021	39.5
2022	33.8
2023	29.4
Later years	130.3
Future minimum payments due	330.9
Vehicles
Operating Leased Assets [Line Items]
2019	9.7
2020	5.5
2021	2.3
2022	0.6
2023	0.1
Later years	0.0
Future minimum payments due	18.2
Other
Operating Leased Assets [Line Items]
2019	21.6
2020	15.5
2021	9.5
2022	5.3
2023	2.3
Later years	0.0
Future minimum payments due	$ 54.2