Regulatory Matters - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2005	Dec. 31, 2019	Dec. 31, 2018
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Proceeds from (repurchase of) trust preferred securities	$ 10	$ 10	$ 10
Tier 1 common equity, adequately capitalized ratio, conservation buffer		2.50%

The cash inflow from issuance of trust preferred securities, net of the cash outflow for repurchasing trust preferred securities, by a business trust or other special purpose entity, mainly established by a bank holding entity, to third party investors. The trust's assets are deeply subordinated debentures of the bank holding entity. Most trust preferred securities are subject to a mandatory redemption upon the repayment of the debentures.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Name:	us-gaap_ProceedsFromRepurchaseOfTrustPreferredSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration