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Intangible Assets - Schedule of Changes in the Components of Acquired Client Relationships (Details) (USD $) In Millions, unless otherwise specified |  |  | 9 Months Ended
--- | --- | --- | ---
Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 Acquired Client Relationships
Definite-lived |  |  |
Beginning balance, gross (in dollars) |  |  | $ 1,039.5
Beginning balance, accumulated amortization |  |  | (442.8)
Beginning balance, net (in dollars) |  |  | 596.7
New investments |  |  | 149.6
Amortization and impairments |  |  | (84.2)
Foreign currency translation |  |  | (1.3)
Ending balance, gross (in dollars) |  |  | 1,187.8
Ending balance, accumulated amortization |  |  | (527.0)
Ending balance, net (in dollars) |  |  | 660.8
Indefinite-lived |  |  |
Beginning balance, net (in dollars) |  |  | 864.0
New investments |  |  | 46.8
Amortization and impairments |  |  | 0
Foreign currency translation |  |  | (5.0)
Ending balance, net (in dollars) |  |  | 905.8
Total |  |  |
Beginning balance, net (in dollars) | 1,566.6 | 1,460.7 | 1,460.7
New investments |  |  | 196.4
Amortization and impairments |  |  | (84.2)
Foreign currency translation |  |  | (6.3)
Ending balance, net (in dollars) | $ 1,566.6 | $ 1,460.7 | $ 1,566.6

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