Results of Operations and Average Assets by Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Segment Reporting Information [Line Items]
Other Asset Impairment Charges	$ 30us-gaap_OtherAssetImpairmentCharges
Operating lease equipment
Segment Reporting Information [Line Items]
Other Asset Impairment Charges	30
Branch Banking
Segment Reporting Information [Line Items]
Impairment Of Real Estate	$ 4

The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

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