Securities - Certain Corporate and Strategic Investments (Details) (USD $) Share data in Billions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
First Data Corporation [Member]
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investment, Ownership Percentage	49.00%
Equity Method Investments	$ 3,300,000,000	$ 3,300,000,000
Common Stock [Member] \| China Construction Bank [Member]
Cost Method Investments [Abstract]
Investment Owned, Balance, Shares	2.0	2.0
Cost method investment ownership percentage	1.00%	1.00%
Cost Method Investment, Cost Basis	716,000,000
Cost-method Investments, Aggregate Carrying Amount	$ 1,500,000,000	$ 1,400,000,000

This element represents the aggregate carrying amount of all cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment. The cost method and lower-of-cost or market, an adaptation of the cost method, is generally followed for most investments in noncontrolled corporations, in some corporate joint ventures, and to a lesser extent in unconsolidated subsidiaries, particularly foreign.

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-Publisher AICPA

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

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Name Emerging Issues Task Force (EITF)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References+ Details

- Definition

Balance held at close of period in number of shares.

+ References+ Details