Loan Servicing - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Transfers and Servicing [Abstract]
Payment for settlement of FHA matter	$ 83
Separate recoveries on FHA matter	71
Net benefit related to FHA matter	73
Release of mortgage repurchase reserves	$ 31

Amount of cash outflow reducing loss contingency liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Name:	us-gaap_LossContingencyAccrualPayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration