Investment Securities (Schedule of Available-for-sale Securities Reconciliation) (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 13,587,000,000	$ 15,167,000,000
Available-for-sale Securities, Gross Unrealized Gains	269,000,000	197,000,000
Available-for-sale Securities, Gross Unrealized Losses	(86,000,000)	(229,000,000)
Available-for-sale Securities	13,770,000,000	15,135,000,000
Total agency backed bonds	4,580,000,000	6,114,000,000
Deposit Assets	15,000,000	16,000,000
Cash Equivalents, at Carrying Value	7,300,000,000	5,600,000,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	12,473,000,000	13,979,000,000
Available-for-sale Securities, Gross Unrealized Gains	241,000,000	172,000,000
Available-for-sale Securities, Gross Unrealized Losses	(14,000,000)	(75,000,000)
Available-for-sale Securities	12,700,000,000	14,076,000,000
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,354,000,000	1,535,000,000
Available-for-sale Securities, Gross Unrealized Gains	4,000,000	13,000,000
Available-for-sale Securities, Gross Unrealized Losses	0	(2,000,000)
Available-for-sale Securities	1,358,000,000	1,546,000,000
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	0	1,000,000
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities	0	1,000,000
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	803,000,000	765,000,000
Available-for-sale Securities, Gross Unrealized Gains	17,000,000	20,000,000
Available-for-sale Securities, Gross Unrealized Losses	0	(1,000,000)
Available-for-sale Securities	820,000,000	784,000,000
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	6,269,000,000	7,266,000,000
Available-for-sale Securities, Gross Unrealized Gains	114,000,000	87,000,000
Available-for-sale Securities, Gross Unrealized Losses	(9,000,000)	(41,000,000)
Available-for-sale Securities	6,374,000,000	7,312,000,000
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,365,000,000	2,600,000,000
Available-for-sale Securities, Gross Unrealized Gains	47,000,000	28,000,000
Available-for-sale Securities, Gross Unrealized Losses	(1,000,000)	(13,000,000)
Available-for-sale Securities	2,411,000,000	2,615,000,000
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,349,000,000	1,486,000,000
Available-for-sale Securities, Gross Unrealized Gains	59,000,000	23,000,000
Available-for-sale Securities, Gross Unrealized Losses	(4,000,000)	(18,000,000)
Available-for-sale Securities	1,404,000,000	1,491,000,000
Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	333,000,000	326,000,000
Available-for-sale Securities, Gross Unrealized Gains	0	1,000,000
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities	333,000,000	327,000,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,114,000,000	1,188,000,000
Available-for-sale Securities, Gross Unrealized Gains	28,000,000	25,000,000
Available-for-sale Securities, Gross Unrealized Losses	(72,000,000)	(154,000,000)
Available-for-sale Securities	$ 1,070,000,000	$ 1,059,000,000

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

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

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-Name Statement of Financial Accounting Standard (FAS)

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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 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-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

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-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 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-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 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section 25

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-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash equivalents may be reported as cash equivalents, while legally restricted equivalents held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular equivalents are not generally reported as part of unrestricted cash equivalents.

+ References+ Details