Derivatives and Hedging Activities - OTC Derivatives by Product Type and Tenor (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative Assets	$ 54,744	$ 53,890
Derivative Liabilities	44,439	46,771
OTC [Member]
Derivative [Line Items]
Derivative Assets	173,457	160,020
Derivative Liabilities	113,602	104,566
OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	129,291	108,910
Derivative Liabilities	73,285	54,860
OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	11,497	12,053
Derivative Liabilities	8,152	7,945
OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	27,906	29,935
Derivative Liabilities	24,992	32,366
OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	5,340	10,356
Derivative Liabilities	6,936	10,126
OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	13,674	13,447
Derivative Liabilities	14,488	13,950
OTC [Member] | Counterparty Netting Within Tenors [Member]
Derivative [Line Items]
Derivative Assets	(14,251)	(14,681)
Derivative Liabilities	(14,251)	(14,681)
OTC [Member] | Cross Tenor Counterparty Netting [Member]
Derivative [Line Items]
Derivative Assets	(21,980)	(20,462)
Derivative Liabilities	(21,980)	(20,462)
OTC [Member] | Cash Collateral Netting [Member]
Derivative [Line Items]
Cash collateral netting	(98,608)	(89,132)
Cash collateral netting	(49,047)	(39,950)
OTC [Member] | Counterparty and Cash Collateral Netting [Member]
Derivative [Line Items]
Derivative Assets	52,869	50,426
Derivative Liabilities	42,575	44,154
Less than 1 Year [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	22,493	27,915
Derivative Liabilities	24,640	25,463
Less than 1 Year [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	6,008	4,231
Derivative Liabilities	7,662	5,323
Less than 1 Year [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	1,646	1,664
Derivative Liabilities	2,513	1,804
Less than 1 Year [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	11,981	14,646
Derivative Liabilities	10,623	12,378
Less than 1 Year [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	3,094	6,228
Derivative Liabilities	2,922	4,464
Less than 1 Year [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	3,551	4,806
Derivative Liabilities	4,707	5,154
Less than 1 Year [Member] | OTC [Member] | Counterparty Netting Within Tenors [Member]
Derivative [Line Items]
Derivative Assets	(3,787)	(3,660)
Derivative Liabilities	(3,787)	(3,660)
1 - 5 Years [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	37,917	41,998
Derivative Liabilities	26,802	31,776
1 - 5 Years [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	22,669	23,278
Derivative Liabilities	12,921	13,945
1 - 5 Years [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	3,264	4,547
Derivative Liabilities	3,548	4,704
1 - 5 Years [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	6,832	8,936
Derivative Liabilities	7,262	9,940
1 - 5 Years [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	2,024	3,897
Derivative Liabilities	1,351	3,136
1 - 5 Years [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	8,478	7,091
Derivative Liabilities	7,070	5,802
1 - 5 Years [Member] | OTC [Member] | Counterparty Netting Within Tenors [Member]
Derivative [Line Items]
Derivative Assets	(5,350)	(5,751)
Derivative Liabilities	(5,350)	(5,751)
Greater than 5 Years [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	113,047	90,107
Derivative Liabilities	62,160	47,327
Greater than 5 Years [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	100,614	81,401
Derivative Liabilities	52,702	35,592
Greater than 5 Years [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	6,587	5,842
Derivative Liabilities	2,091	1,437
Greater than 5 Years [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	9,093	6,353
Derivative Liabilities	7,107	10,048
Greater than 5 Years [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	222	231
Derivative Liabilities	2,663	2,526
Greater than 5 Years [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	1,645	1,550
Derivative Liabilities	2,711	2,994
Greater than 5 Years [Member] | OTC [Member] | Counterparty Netting Within Tenors [Member]
Derivative [Line Items]
Derivative Assets	(5,114)	(5,270)
Derivative Liabilities	$ (5,114)	$ (5,270)