Goodwill and Other Intangible Assets (Details 1) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	$ 722.0	$ 733.7
Intangible assets, Accumulated Amortization	392.7	373.8
Intangible assets, Net Carrying Amount	329.3	359.9
Intangible assets not subject to amortization:
Trade name	51.0	52.0
FAA air agency certificates	8.7	8.7
Indefinite Lived Intangible Assets Net	59.7	60.7
Total intangible assets, Gross Carrying Amount	781.7	794.4
Total intangible assets, Net Carrying Amount	389.0	420.6
Customer Relationships [Member]
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	315.0	324.6
Intangible assets, Accumulated Amortization	113.2	103.0
Intangible assets, Net Carrying Amount	201.8	221.6
Technology-Based Intangible Assets [Member]
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	127.4	128.7
Intangible assets, Accumulated Amortization	37.0	33.8
Intangible assets, Net Carrying Amount	90.4	94.9
Trademarks [Member]
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	7.7	8.6
Intangible assets, Accumulated Amortization	4.5	4.3
Intangible assets, Net Carrying Amount	3.2	4.3
Computer Software, Intangible Asset [Member]
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	261.8	261.5
Intangible assets, Accumulated Amortization	231.8	226.5
Intangible assets, Net Carrying Amount	30.0	35.0
Unclassified Indefinite-lived Intangible Assets [Member]
Intangible assets subject to amortization:
Intangible assets, Gross Carrying Amount	10.1	10.3
Intangible assets, Accumulated Amortization	6.2	6.2
Intangible assets, Net Carrying Amount	$ 3.9	$ 4.1