Commitments and Contingencies (Lease Commitments) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating and Capital Leased Assets [Line Items] [Line Items]
Expenses under real property, equipment, and sofware leases		$ 66.2	$ 56.3	$ 52.8
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Noncancelable Lease Commitments, Capital, 2019		35.7
Noncancelable Lease Commitments, Capital, 2020		10.4
Noncancelable Lease Commitments, Capital, 2021		10.1
Noncancelable Lease Commitments, Capital, 2022		10.2
Noncancelable Lease Commitments, Capital, 2023		10.1
Noncancelable Lease Commitments, Capital, Thereafter		108.7
Noncancelable Lease Commitments, Capital, Total minimum payments		185.2
Noncancelable Lease Commitments, Capital, Amounts representing interest		(69.5)
Noncancelable Lease Commitments, Capital, Total		115.7
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Noncancelable Lease Commitments, Operating, 2019	[1]	61.2
Noncancelable Lease Commitments, Operating, 2020	[1]	51.0
Noncancelable Lease Commitments, Operating, 2021	[1]	46.1
Noncancelable Lease Commitments, Operating, 2022	[1]	42.1
Noncancelable Lease Commitments, Operating, 2023	[1]	36.6
Noncancelable Lease Commitments, Operating, Thereafter	[1]	258.4
Noncancelable Lease Commitments, Operating, Total minimum payments	[1]	495.4
Minimum sublease income		$ 2.2
Minimum [Member]
Operating and Capital Leased Assets [Line Items] [Line Items]
Operating leases, term of contract		1 year
Maximum [Member]
Operating and Capital Leased Assets [Line Items] [Line Items]
Operating leases, term of contract		25 years

[1] Future minimum operating lease payments do not reflect future minimum sublease income of $2.2 million. Additionally, operating leases that are on a month-to-month basis are not included.