Acquisitions and Discontinued Operations - Components of Income (Loss) from Discontinued Operations, Net of Taxes, of Education Lending Business Acquisitions and Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	$ 572	$ 549	$ 1,663	$ 1,710
Provision for loan and lease losses			171	37
Net interest income (expense) after provision for loan and lease losses	463	539	1,491	1,748
Noninterest income	(544)	(483)	(1,501)	(1,394)
Noninterest expense	734	692	2,151	2,073
Income taxes	(52)	(95)	(184)	(300)
Income (loss) from discontinued operations, net of taxes		(17)	5	(37)
Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	28	35	89	106
Provision for loan and lease losses	(2)	37	4	99
Net interest income (expense) after provision for loan and lease losses	30	(2)	85	7
Noninterest income	(21)	(16)	(41)	(36)
Noninterest expense	9	10	36	31
Income (loss) before income taxes		(28)	8	(60)
Income taxes		11	(3)	23
Income (loss) from discontinued operations, net of taxes		(17)	5	(37)
Education Lending [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) before income taxes		(28)	17	(60)
Income taxes		(10)	6	(22)
Income (loss) from discontinued operations, net of taxes		(18)	11	(38)
Education Lending [Member] \| Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	28	35	89	106
Provision for loan and lease losses	(2)	37	4	99
Net interest income (expense) after provision for loan and lease losses	30	(2)	85	7
Noninterest income	(21)	(16)	(41)	(37)
Noninterest expense	$ 9	$ 10	$ 27	$ 30

Acquisitions and Discontinued Operations - Components of Income (Loss) from Discontinued Operations, Net of Taxes, of Education Lending Business Acquisitions and Discontinued Operations (Detail) (USD $)
In Millions, unless otherwise specified

3 Months Ended

9 Months Ended

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2012

Sep. 30, 2011

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Net interest income

$ 572

$ 549

$ 1,663

$ 1,710

Provision for loan and lease losses

171

Net interest income (expense) after provision for loan and lease losses

463

539

1,491

1,748

Noninterest income

(544)

(483)

(1,501)

(1,394)

Noninterest expense

734

692

2,151

2,073

Income taxes

(52)

(95)

(184)

(300)

Income (loss) from discontinued operations, net of taxes

(17)

(37)

Segment, Discontinued Operations [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Net interest income

106

Provision for loan and lease losses

(2)

Net interest income (expense) after provision for loan and lease losses

(2)

Noninterest income

(21)

(16)

(41)

(36)

Noninterest expense

Income (loss) before income taxes

(28)

(60)

Income taxes

(3)

Income (loss) from discontinued operations, net of taxes

(17)

(37)

Education Lending [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Income (loss) before income taxes

(28)

(60)

Income taxes

(10)

(22)

Income (loss) from discontinued operations, net of taxes

(18)

(38)

Education Lending [Member] | Segment, Discontinued Operations [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Net interest income

106

Provision for loan and lease losses

(2)

Net interest income (expense) after provision for loan and lease losses

(2)

Noninterest income

(21)

(16)

(41)

(37)

Noninterest expense

$ 9

$ 10

$ 27

$ 30

- Definition

Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References+ Details

- Definition

Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 13

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 47

-Subparagraph c

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Article 5

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

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 29

-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

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.14)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 43

-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 Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.12)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

+ Details

- Definition

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

+ References+ Details

- Definition

The sum of the periodic provision charged to earnings, based on an assessment of uncollectibility from the counterparty on account of loan, lease or other credit losses, to reduce these accounts to the amount that approximates their net realizable value.

+ References+ Details