Borrowings - Stated Maturities and Maturity to Call Date (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
2013	$ 13,700
2014	19,700
2015	11,900
2016	12,400
2017	12,500
2018-2047	80,300
Total, long-term debt	152,401	154,393
Stated Maturity [Member]
Debt Instrument [Line Items]
2013	13,655
2014	19,652
2015	11,868
2016	12,293
2017	12,399
2018-2047	79,745
Long term debt maturities total	149,612
Hedge accounting adjustments	2,789
Total, long-term debt	152,401
Stated Maturity [Member] \| Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
2013
2014	3,021
2015	997
2016	2,277
2017	1,823
2018-2047	7,328
Long term debt maturities total	15,446
Hedge accounting adjustments	1,644
Total, long-term debt	17,090
Stated Maturity [Member] \| Brokered Deposits [Member]
Debt Instrument [Line Items]
2013
2014	1,738
2015	708
2016	235
2017	407
2018-2047
Long term debt maturities total	3,088
Hedge accounting adjustments	32
Total, long-term debt	3,120
Stated Maturity [Member] \| Secured Borrowings [Member]
Debt Instrument [Line Items]
2013	13,655
2014	14,893
2015	10,163
2016	9,781
2017	10,169
2018-2047	72,417
Long term debt maturities total	131,078
Hedge accounting adjustments	1,113
Total, long-term debt	132,191
Maturity to Call Date [Member]
Debt Instrument [Line Items]
2013	20,444
2014	15,411
2015	11,733
2016	12,292
2017	12,377
2018-2047	77,355
Long term debt maturities total	149,612
Hedge accounting adjustments	2,789
Total, long-term debt	152,401
Maturity to Call Date [Member] \| Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
2013	1,563
2014	3,158
2015	1,086
2016	2,276
2017	1,801
2018-2047	5,562
Long term debt maturities total	15,446
Hedge accounting adjustments	1,644
Total, long-term debt	17,090
Maturity to Call Date [Member] \| Brokered Deposits [Member]
Debt Instrument [Line Items]
2013
2014	1,738
2015	708
2016	235
2017	407
2018-2047
Long term debt maturities total	3,088
Hedge accounting adjustments	32
Total, long-term debt	3,120
Maturity to Call Date [Member] \| Secured Borrowings [Member]
Debt Instrument [Line Items]
2013	18,881
2014	10,515
2015	9,939
2016	9,781
2017	10,169
2018-2047	71,793
Long term debt maturities total	131,078
Hedge accounting adjustments	1,113
Total, long-term debt	$ 132,191

ASC eight one five fair value adjustments.

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- Definition

Long term debt maturities.

+ References

No definition available.

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

Reference 2: 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)

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-Publisher FASB

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

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-Article 9

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

-Publisher SEC

-Name Regulation S-X (SX)

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-Paragraph 20, 22

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

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- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year.

+ References

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year.

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year.

+ References

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year.

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year.

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