Operating Leases (Schedule of Future Commitments Under Non-Cancelable Operating Leases) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	$ 59.7
2019	61.6
2020	53.6
2021	50.7
2022	48.5
Thereafter	90.4
Gross lease commitments	364.5
Less: future minimum payments expected to be received under non-cancelable subleases	6.7
Net lease commitments	357.8
Building [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	57.6
2019	59.6
2020	51.6
2021	49.8
2022	48.5
Thereafter	90.4
Gross lease commitments	357.5
Less: future minimum payments expected to be received under non-cancelable subleases	6.7
Net lease commitments	350.8
Other [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	2.1
2019	2.0
2020	2.0
2021	0.9
2022	0.0
Thereafter	0.0
Gross lease commitments	7.0
Less: future minimum payments expected to be received under non-cancelable subleases	0.0
Net lease commitments	$ 7.0