Loans - Consumer, Excluding Credit Card Loan Portfolio, Loan Modifications, New TDRs (Details) - Consumer, excluding credit card - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Total residential real estate – excluding PCI
Financing Receivable, Impaired [Line Items]
New TDRs	$ 135	$ 250
Residential mortgage
Financing Receivable, Impaired [Line Items]
New TDRs	69	147
Home equity
Financing Receivable, Impaired [Line Items]
New TDRs	$ 66	$ 103

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration