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Goodwill and Acquired Client Relationships - Schedule of Changes in Goodwill (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015
Goodwill |  |
Goodwill impairment | $ 0 | $ 0
Changes in goodwill |  |
Balance at the beginning of the period | 2,668,400,000 | 2,652,800,000
Goodwill acquired | 0 | 64,300,000
Foreign currency translation | (40,300,000) | (48,700,000)
Balance at the end of the period | 2,628,100,000 | 2,668,400,000
Institutional |  |
Changes in goodwill |  |
Balance at the beginning of the period | 1,141,300,000 | 1,159,100,000
Goodwill acquired | 0 | 9,200,000
Foreign currency translation | (5,100,000) | (27,000,000)
Balance at the end of the period | 1,136,200,000 | 1,141,300,000
Mutual Fund |  |
Changes in goodwill |  |
Balance at the beginning of the period | 1,119,500,000 | 1,125,300,000
Goodwill acquired | 0 | 0
Foreign currency translation | (37,000,000) | (5,800,000)
Balance at the end of the period | 1,082,500,000 | 1,119,500,000
High Net Worth |  |
Changes in goodwill |  |
Balance at the beginning of the period | 407,600,000 | 368,400,000
Goodwill acquired | 0 | 55,100,000
Foreign currency translation | 1,800,000 | (15,900,000)
Balance at the end of the period | $ 409,400,000 | $ 407,600,000

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