Commitments, Contingent Liabilities and Guarantees - Commitments to Extend Credit or Funding (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Guarantor Obligations [Line Items]
Total loan commitments	$ 38,870	$ 36,365
When-issued and to be announced securities commitments	102	140
Commercial letters of credit	121	119
Purchase card commitments	63	34
Principal investing commitments	60	75
Liabilities of certain limited partnerships and other commitments	1	2
Total loan and other commitments	39,217	36,735
Commercial and Other [Member]
Guarantor Obligations [Line Items]
Total loan commitments	25,979	23,611
Commercial Real Estate and Construction [Member]
Guarantor Obligations [Line Items]
Total loan commitments	1,965	2,104
Home Equity [Member]
Guarantor Obligations [Line Items]
Total loan commitments	7,164	7,193
Credit Cards [Member]
Guarantor Obligations [Line Items]
Total loan commitments	$ 3,762	$ 3,457