Consolidations and Transfers of Financial Assets Unconsolidated VIE narrative (Details) - Unconsolidated VIEs [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Collateralized mortgage backed securities [Member]
Variable Interest Entities [Line Items]
Maximum exposure to loss related to unconsolidated MBS	$ 34,434	$ 45,311
Total assets of unconsolidated mortgage-backed trusts	220,000	250,000
Partnership Interest [Member]
Variable Interest Entities [Line Items]
Total assets of unconsolidated mortgage-backed trusts	$ 4,900	$ 5,800

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=52262685&loc=d3e5728-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=52262685&loc=d3e5747-111685

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