Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill by Reportable Segment (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Beginning balance	$ 6,344	$ 6,323
Goodwill, Acquired During Period	32	20
Goodwill, Intersegment Transfers	0
Contingent consideration		1
Goodwill, Impairment Loss	(7)	0	0
Ending balance	6,369	6,344	6,323
Retail Banking [Member]
Beginning balance	4,854	4,854
Goodwill, Acquired During Period	0	0
Goodwill, Intersegment Transfers	(4,854)
Contingent consideration		0
Goodwill, Impairment Loss	0
Ending balance	0	4,854
Wealth and Investment Management [Member]
Beginning balance	382	361
Goodwill, Acquired During Period	0	20
Goodwill, Intersegment Transfers	(382)
Contingent consideration		1
Goodwill, Impairment Loss	0
Ending balance	0	382
Diversified Commercial Banking [Member]
Beginning balance	928	928
Goodwill, Acquired During Period	0	0
Goodwill, Intersegment Transfers	(928)
Contingent consideration		0
Goodwill, Impairment Loss	0
Ending balance	0	928
Corporate and Investment Banking [Member]
Beginning balance	180	180
Goodwill, Acquired During Period	0	0
Goodwill, Intersegment Transfers	(180)
Contingent consideration		0
Goodwill, Impairment Loss	0
Ending balance	0	180
Wholesale Banking [Member]
Beginning balance	0	0
Goodwill, Acquired During Period	0	0
Goodwill, Intersegment Transfers	2,414
Contingent consideration		0
Goodwill, Impairment Loss	0
Ending balance	2,414	0
Consumer Banking and Private Wealth Management [Member]
Beginning balance	0	0
Goodwill, Acquired During Period	32	0
Goodwill, Intersegment Transfers	3,930
Contingent consideration		0
Goodwill, Impairment Loss	(7)
Ending balance	3,955	0
Wholesale Banking [Member] \| Retail Banking [Member]
Goodwill, Intersegment Transfers	1,300
Wholesale Banking [Member] \| Wealth and Investment Management [Member]
Goodwill, Intersegment Transfers	47
Wholesale Banking [Member] \| Diversified Commercial Banking [Member]
Goodwill, Intersegment Transfers	928
Wholesale Banking [Member] \| Corporate and Investment Banking [Member]
Goodwill, Intersegment Transfers	$ 180

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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+ Details

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details

- Definition

Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

+ References

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

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-Publisher FASB

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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.

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+ Details