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Intangible Assets - Schedule of Changes in the Components of Acquired Client Relationships (Details) (USD $) In Millions, unless otherwise specified |  |  | 6 Months Ended
--- | --- | --- | ---
Jun. 30, 2014 | Dec. 31, 2013 | Jun. 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 |  |  | 149.1
Amortization and impairments |  |  | (55.5)
Foreign currency translation |  |  | 0.4
Ending balance, gross (in dollars) |  |  | 1,189.0
Ending balance, accumulated amortization |  |  | (498.3)
Ending balance, net (in dollars) |  |  | 690.7
Indefinite-lived |  |  |
Beginning balance, net (in dollars) |  |  | 864.0
New investments |  |  | 46.8
Amortization and impairments |  |  | 0
Foreign currency translation |  |  | 8.1
Ending balance, net (in dollars) |  |  | 918.9
Total |  |  |
Beginning balance, net (in dollars) | 1,609.6 | 1,460.7 | 1,460.7
New investments |  |  | 195.9
Amortization and impairments |  |  | (55.5)
Foreign currency translation |  |  | 8.5
Ending balance, net (in dollars) | $ 1,609.6 | $ 1,460.7 | $ 1,609.6

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