Loans and Loans Held for Sale - Summary of Changes in Loans Held for Sale (Detail) - USD ($) $ in Millions	3 Months Ended
Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Loans Receivables [Abstract]
Balance at beginning of the period	$ 835	$ 784	$ 435
New originations	1,673	2,465	1,593
Transfers from (to) held to maturity, net	24	2
Loan sales	(1,616)	(2,516)	(1,243)
Loan draws (payments), net		(1)	(1)
Balance at end of period	$ 916	$ 734	$ 784

Loans receivable held for sale reconciliation to cash flow transfers held to maturity net.

No definition available.

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- Definition

Loans Receivables [Abstract]

+ References

No definition available.

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- Definition

Amount classified as loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 35

-Paragraph 49

-URI http://asc.fasb.org/extlink&oid=35742846&loc=d3e3084-111518

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section 30

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6490209&loc=d3e48214-111002

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

+ Details

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- Definition

Reconcile the changes in loans that will be sold to other entities balances to the amounts presented in the consolidated statement of cash flows. Enter the additions to trade accounts that will be sold to other entities for the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

+ Details

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- Definition

Reconcile the changes in loans that will be sold to other entities balances to the amounts presented in the consolidated statement of cash flows. Enter the deductions to trade accounts that will be sold to other entities for the period.

+ References

+ Details

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- Definition

The aggregate cash outflow used to purchase all loans that are held with the intention to resell in the near future.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 230

-Section 55

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=34726456&loc=d3e60097-112785

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3367-108585

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 21

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3461-108585

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