Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	$ 21,985	$ 27,284
Trading liabilities	2,670	5,397
U.S. Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	2,352	5,145
US Government agency issued or guaranteed [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	45	0
US Government-sponsored enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	246	192
Asset-backed securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	0	143
Foreign bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	768	7,971
Equity securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	13,287	6,043
Precious metals [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	3,316	4,989
Trading liabilities	90	2,312
Securities sold, not yet purchased [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	947	727
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	1,971	2,801
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	$ 1,633	$ 2,358