Derivatives and Hedging Activities - OTC Derivatives by Product Type and Tenor (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Assets	$ 45,194	$ 53,672
Derivative Liabilities	39,007	47,499
OTC [Member]
Derivative [Line Items]
Derivative Assets	137,520	153,850
Derivative Liabilities	90,792	105,799
OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	100,500	103,728
Derivative Liabilities	48,951	55,305
OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	8,932	9,347
Derivative Liabilities	5,911	6,555
OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	24,115	35,064
Derivative Liabilities	25,128	30,370
OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	4,530	4,867
Derivative Liabilities	5,891	6,416
OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	11,548	13,731
Derivative Liabilities	17,016	20,040
OTC [Member] | Counterparty Netting in Tenors [Member]
Derivative [Line Items]
Derivative Assets	(12,105)	(12,887)
Derivative Liabilities	(12,105)	(12,887)
OTC [Member] | Cross Tenor Counterparty Netting [Member]
Derivative [Line Items]
Derivative Assets	(17,421)	(17,396)
Derivative Liabilities	(17,421)	(17,396)
OTC [Member] | Cash Collateral Netting [Member]
Derivative [Line Items]
Cash collateral netting	(76,941)	(85,329)
Cash collateral netting	(36,203)	(42,986)
OTC [Member] | Counterparty and Cash Collateral Netting [Member]
Derivative [Line Items]
Derivative Assets	43,158	51,125
Derivative Liabilities	37,168	45,417
Less than 1 Year [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	19,866	28,823
Derivative Liabilities	25,256	28,462
Less than 1 Year [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	5,419	5,845
Derivative Liabilities	5,086	5,679
Less than 1 Year [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	1,295	1,763
Derivative Liabilities	1,298	2,060
Less than 1 Year [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	9,715	18,344
Derivative Liabilities	11,591	14,720
Less than 1 Year [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	3,103	3,273
Derivative Liabilities	2,387	2,546
Less than 1 Year [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	3,299	3,141
Derivative Liabilities	7,859	7,000
Less than 1 Year [Member] | OTC [Member] | Counterparty Netting in Tenors [Member]
Derivative [Line Items]
Derivative Assets	(2,965)	(3,543)
Derivative Liabilities	(2,965)	(3,543)
1 - 5 Years [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	30,578	34,477
Derivative Liabilities	23,524	30,344
1 - 5 Years [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	17,823	18,376
Derivative Liabilities	9,749	10,814
1 - 5 Years [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	3,476	2,695
Derivative Liabilities	3,082	3,328
1 - 5 Years [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	6,246	8,292
Derivative Liabilities	8,502	9,771
1 - 5 Years [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	1,252	1,415
Derivative Liabilities	1,067	1,555
1 - 5 Years [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	6,955	9,249
Derivative Liabilities	6,298	10,426
1 - 5 Years [Member] | OTC [Member] | Counterparty Netting in Tenors [Member]
Derivative [Line Items]
Derivative Assets	(5,174)	(5,550)
Derivative Liabilities	(5,174)	(5,550)
Greater than 5 Years [Member] | OTC [Member]
Derivative [Line Items]
Derivative Assets	87,076	90,550
Derivative Liabilities	42,012	46,993
Greater than 5 Years [Member] | OTC [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Assets	77,258	79,507
Derivative Liabilities	34,116	38,812
Greater than 5 Years [Member] | OTC [Member] | Credit Risk Contract [Member]
Derivative [Line Items]
Derivative Assets	4,161	4,889
Derivative Liabilities	1,531	1,167
Greater than 5 Years [Member] | OTC [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Assets	8,154	8,428
Derivative Liabilities	5,035	5,879
Greater than 5 Years [Member] | OTC [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative Assets	175	179
Derivative Liabilities	2,437	2,315
Greater than 5 Years [Member] | OTC [Member] | Equity Contract [Member]
Derivative [Line Items]
Derivative Assets	1,294	1,341
Derivative Liabilities	2,859	2,614
Greater than 5 Years [Member] | OTC [Member] | Counterparty Netting in Tenors [Member]
Derivative [Line Items]
Derivative Assets	(3,966)	(3,794)
Derivative Liabilities	$ (3,966)	$ (3,794)