Commitments, Contingent Liabilities and Guarantees - Commitments to Extend Credit or Funding (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Guarantor Obligations [Line Items]
Total loan commitments	$ 52,725	$ 40,594
When-issued and to be announced securities commitments	34	2
Commercial letters of credit	143	139
Purchase card commitments	293	163
Principal investing commitments	37	50
Tax credit investment commitments	466	410
Liabilities of certain limited partnerships and other commitments	2	1
Total loan and other commitments	53,700	41,359
Commercial and Other [Member]
Guarantor Obligations [Line Items]
Total loan commitments	34,372	28,053
Commercial Real Estate and Construction [Member]
Guarantor Obligations [Line Items]
Total loan commitments	3,034	1,718
Home Equity [Member]
Guarantor Obligations [Line Items]
Total loan commitments	9,666	7,220
Credit Cards [Member]
Guarantor Obligations [Line Items]
Total loan commitments	$ 5,653	$ 3,603