Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	$ 28,452	$ 21,978
Trading liabilities	3,235	3,643
U.S. Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	6,763	5,368
US Government agency issued or guaranteed [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	18	111
US Government-sponsored enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	20	41
Asset-backed securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	168	208
Corporate and foreign bonds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	10,826	10,562
Equity securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	5,693	751
Precious metals [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	1,909	1,889
Trading liabilities	124	215
Securities sold, not yet purchased [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	1,182	738
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading assets	3,055	3,048
Derivatives, net [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading liabilities	$ 1,929	$ 2,690