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Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Other Intangible Assets (Details) € in Millions, $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			$ 1,827		$ 1,816	$ 1,827	$ 1,827
Acquisitions					0		264
Amortization	$ (58)	$ (62)			(179)	(183)	(245)
Foreign currency translation					(69)		(30)
Ending balance	1,568				1,568		1,816
Investment Servicing
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			1,733		1,746	1,733	1,733
Acquisitions					0		264
Amortization					(163)		(221)
Foreign currency translation					(69)		(30)
Ending balance	1,514				1,514		1,746
Investment Servicing \| Fideuram Bank Luxembour
Finite-lived Intangible Assets [Roll Forward]
Payment for acquisition			258	€ 220
Investment Servicing \| Mercatus, Inc
Finite-lived Intangible Assets [Roll Forward]
Payment for acquisition		$ 88
Investment Management
Finite-lived Intangible Assets [Roll Forward]
Beginning balance			$ 94		70	$ 94	94
Acquisitions					0		0
Amortization					(16)		(24)
Foreign currency translation					0		0
Ending balance	$ 54				$ 54		$ 70