Reserves on Deposit with the Federal Reserve Bank and Federal Bank Stock - Shares Held at Federal Reserve Bank and Federal Home Loan Bank (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Federal Home Loan Bank Stock and Federal Reserve Bank Stock [Abstract]
FHLB stock holdings	$ 26	$ 17
FRB stock holdings	$ 81	$ 44

Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123599499&loc=d3e63345-112809

Name:	us-gaap_FederalReserveBankStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant