Amount, after troubled debt restructuring, of modified financing receivable.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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

Loans and asset quality - Loan Modifications (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding recorded investment post-modification (less than)	$ 282
Other residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding recorded investment post-modification (less than)		$ 1	$ 1