Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	$ 33,754	$ 28,452
Trading liabilities	3,517	3,235
U.S. Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	5,603	6,763
US Government agency issued or guaranteed [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	16	18
US Government-sponsored enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	177	20
Asset-backed securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	147	168
Corporate and foreign bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	9,190	10,826
Equity securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	6,169	5,693
Precious metals [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	9,536	1,909
Trading liabilities	0	124
Securities sold, not yet purchased [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	695	1,182
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	2,916	3,055
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	$ 2,822	$ 1,929