Investment Securities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012 years	Dec. 30, 2011	Dec. 31, 2011 years	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Future Prepayment Rate Assumption Of Investment Portfolio	11.00%		14.00%
Weighted average life of interest-only securities	5.7		3.0
Weighted average life of principal-only securities	6.4		2.6
Prepayment rate over remaining life of aggregate investment portfolio		14.00%
Unrealized gain on interest-only and principal-only securities	$ (17)		$ (16)	$ 1
Fair value of CMO securities and interest-only strips	719		426
Fair value of CMO securities and interest-only securities including net asset value	1,300		429
CMO and Interest Only, Pricincipal Only Securities, Maximum Loss Exposure	343		155
Fair value of agency securities collaterizing debt issued by securitization trust	1,500		58
Principal balance of agency securities collaterizing debt issued by securitization trust	1,400	55
Other Long-term Debt	$ 937		$ 54

CMO and Interest Only and Pricincipal Only Securities, Maximum Loss Exposure

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- Definition

The sum of the fair values, as of the date of each statement of financial position presented, of directly held CMO securities and interest-only securities including retained interest in transfers treated as sales but excluding securities held by consolidated CMO trust.

+ References

No definition available.

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- Definition

Average future constant repayment rate assumption of Investment Portfolio.

+ References

No definition available.

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- Definition

Prepayment Rate Of Remaining Life Of Investment Portfolio

+ References

No definition available.

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- Definition

Principal Balance of Securities Held as Collateral

+ References

No definition available.

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- Definition

The sum of the fair values, as of the date of each statement of financial position presented, of directly held CMO securities and interest-only securities including retained interest in transfers treated as sales and the fair value of securities held by consolidated CMO trusts.

+ References

No definition available.

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- Definition

Unrealized Gain On Derivative Instrument And Trading Securities

+ References

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- Definition

Weighted Average Life of Interest Only Securities

+ References

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- Definition

Weighted average life of principal only securities.

+ References

No definition available.

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- Definition

Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ 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 210.5-02.22)

-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 19, 20, 22

-Article 5

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- Definition

The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5086-111524

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