Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Amount Outstanding	$ 1,565us-gaap_PreferredStockValueOutstanding	$ 1,565us-gaap_PreferredStockValueOutstanding
Floating Rate Non-Cumulative Preferred Stock, Series F ($25 stated value) [Member]
Class of Stock [Line Items]
Shares Outstanding	20,700,000
Dividend Rate	3.549%
Amount Outstanding	517	517
14,950,000 Depositary Shares each representing a one-fortieth interest in a share of Floating Rate Non-Cumulative Preferred Stock, Series G ($1,000 stated value) [Member]
Class of Stock [Line Items]
Shares Outstanding	373,750
Dividend Rate	4.056%
Amount Outstanding	374	374
14,950,000 Depositary Shares each representing a one-fortieth interest in a share of 6.50% Non-Cumulative Preferred Stock, Series H ($1,000 stated value) [Member]
Class of Stock [Line Items]
Shares Outstanding	373,750
Dividend Rate	6.50%
Amount Outstanding	374	374
6,000,000 Depositary shares each representing a one-fourth interest in a share of Adjustable Rate Cumulative Preferred Stock, Series D ($100 stated value) [Member]
Class of Stock [Line Items]
Shares Outstanding	1,500,000
Dividend Rate	4.50%
Amount Outstanding	150	150
$2.8575 Cumulative Preferred Stock ($50 stated value) [Member]
Class of Stock [Line Items]
Shares Outstanding	3,000,000
Dividend Rate	5.715%
Amount Outstanding	$ 150	$ 150

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The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

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- Definition

Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.28)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29

-Article 5

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- Definition

Value of all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by shareholders, which is net of related treasury stock. May be all or a portion of the number of preferred shares authorized. These shares represent the ownership interest of the preferred shareholders.

+ References

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