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Goodwill and Other Intangible Assets - Intangible Assets by Asset Type (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Intangible Assets [Line Items] |  |
Gross Carrying Amount | $ 2,702.6 | $ 2,694.5
Accumulated Amortization | (1,990.4) | (1,797.5)
Net Carrying Amount | 712.2 | 897.0
Customer relationships and contracts |  |
Intangible Assets [Line Items] |  |
Gross Carrying Amount | 2,071.0 | 2,106.8
Accumulated Amortization | (1,625.5) | (1,490.8)
Net Carrying Amount | 445.5 | 616.0
Trade name |  |
Intangible Assets [Line Items] |  |
Gross Carrying Amount | 422.1 | 422.2
Accumulated Amortization | (237.3) | (216.3)
Net Carrying Amount | 184.8 | 205.9
Internally developed software |  |
Intangible Assets [Line Items] |  |
Gross Carrying Amount | 205.8 | 162.6
Accumulated Amortization | (125.4) | (89.6)
Net Carrying Amount | 80.4 | 73.0
Other |  |
Intangible Assets [Line Items] |  |
Gross Carrying Amount | 3.7 | 2.9
Accumulated Amortization | (2.2) | (0.8)
Net Carrying Amount | $ 1.5 | $ 2.1

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