Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	$ 29,217	$ 28,452
Trading liabilities	3,923	3,235
U.S. Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	8,207	6,763
US Government agency issued or guaranteed [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	39	18
US Government-sponsored enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	21	20
Asset-backed securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	156	168
Corporate and foreign bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	9,365	10,826
Equity securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	1,432	5,693
Precious metals [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	4,604	1,909
Trading liabilities	0	124
Securities sold, not yet purchased [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	434	1,182
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	5,393	3,055
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	$ 3,489	$ 1,929