Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 1,320	$ 1,544	$ 1,544
Amortization	(60)	(60)	(239)
Acquisitions	7
Foreign currency translation	(9)		15
Ending balance	1,258		1,320
Investment Servicing
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	1,293	1,495	1,495
Amortization	(55)		(217)
Acquisitions	7
Foreign currency translation	(9)		15
Ending balance	1,236		1,293
Investment Management
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	27	$ 49	49
Amortization	(5)		(22)
Acquisitions	0
Foreign currency translation	0		0
Ending balance	$ 22		$ 27

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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Amount of foreign currency translation gain (loss) which increases (decreases) assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
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Amount of increase (decrease) to assets, excluding financial assets and goodwill, lacking physical substance with a finite life for purchase accounting adjustments.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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