Other Assets (Components of Other Assets) (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Other receivables from brokers, dealers, and clearing organizations		$ 1,748	$ 235
Receivables — interest, dividends, and other		1,180	788
Other investments		1,019	633
Operating lease ROU assets		937	577
Securities borrowed		873	735
Other securities owned at fair value		687	718
Customer contract receivables		579	356
Capitalized contract costs		303	281
Other		457	264
Total other assets	[1]	7,783	4,587
FRB stock		191
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
FHLB stock		$ 29	$ 35

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.