Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	$ 25,822	$ 27,284
Trading liabilities	2,319	5,397
U.S. Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	2,616	5,145
US Government agency issued or guaranteed [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	18	0
US Government-sponsored enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	61	192
Asset-backed securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	153	143
Foreign bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	8,167	7,971
Equity securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	7,750	6,043
Precious metals [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	4,497	4,989
Trading liabilities	0	2,312
Securities sold, not yet purchased [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	655	727
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	2,560	2,801
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	$ 1,664	$ 2,358