Consolidations and Transfers of Financial Assets Managed Loans (Details) - USD ($) $ in Billions	Dec. 31, 2016	Dec. 31, 2015
Consolidations and Transfers of Financial Assets [Abstract]
Securitized loans in unconsolidated portfolio securitization trusts: unpaid principal balance	$ 1.4	$ 1.6

This is the principal amount outstanding for securitized loans only (across all types of loans).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=64830801&loc=d3e107314-111719

Name:	us-gaap_PrincipalAmountOutstandingOnLoansSecuritized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant