GOODWILL - Narrative (Details) - USD ($) $ in Billions	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Alliance Bernstein \| Investment Management
Goodwill [Line Items]
Amortization of intangible assets	$ 4.6	$ 4.6

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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