Credit Risk Concentrations (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk [Line Items]
Credit exposure	$ 1,953,105	$ 1,850,868
Loans	894,765	837,299
On-balance sheet, Derivatives	64,078	59,677
Off-balance sheet	976,702	940,395
Available-for-sale securities	237,965	239,667
Held-to-maturity securities	50,168	49,073
Cash Placed with Banks	380,200	351,000
Obligations of U.S. states and municipalities
Concentration Risk [Line Items]
Trading securities	9,100	7,600
Available-for-sale securities	31,592	33,550
Held-to-maturity securities	14,475	12,802
Recurring
Concentration Risk [Line Items]
On-balance sheet, Derivatives	64,078	59,677
Trading securities	308,000	284,101
Recurring | Obligations of U.S. states and municipalities
Concentration Risk [Line Items]
Trading securities	9,052	7,637
Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	64,078	59,677
Consumer | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	1,115,268	1,050,405
Loans	506,460	476,284
Off-balance sheet	608,688	573,996
Consumer, excluding credit card
Concentration Risk [Line Items]
Loans	364,644	344,821
Consumer, excluding credit card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	419,441	403,299
Loans	364,644	344,821
Off-balance sheet	54,797	58,478
Consumer, Excluding Credit Card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	419,561	403,424
Loans	364,644	344,821
Off-balance sheet	54,797	58,478
Credit card
Concentration Risk [Line Items]
Loans	141,816	131,463
Credit card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	695,707	646,981
Loans	141,816	131,463
Off-balance sheet	553,891	515,518
Wholesale
Concentration Risk [Line Items]
Loans	388,305	361,015
Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	837,837	800,463
Loans	388,305	361,015
Off-balance sheet	368,014	366,399
Receivables from customers and other | Consumer, Excluding Credit Card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	120	125
Receivables from customers and other | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	17,440	13,372
Wholesale-related | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	815,882	783,126
Loans	383,790	357,050
Off-balance sheet	368,014	366,399
Real Estate | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	222	312
Real Estate | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	135,041	116,857
Loans	106,315	92,820
Off-balance sheet	28,504	23,725
Consumer & Retail | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,082	1,573
Consumer & Retail | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	85,435	85,460
Loans	29,842	27,175
Off-balance sheet	54,511	56,712
Technology, Media & Telecommunications | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,227	1,032
Technology, Media & Telecommunications | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	62,950	57,382
Loans	13,845	11,079
Off-balance sheet	47,878	45,271
Industrials | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,615	1,428
Industrials | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	55,449	54,386
Loans	17,150	16,791
Off-balance sheet	36,684	36,167
Healthcare | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,277	2,751
Healthcare | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	47,866	46,053
Loans	15,120	16,965
Off-balance sheet	30,469	26,337
Banks & Finance Cos | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	12,232	10,218
Banks & Finance Cos | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	44,614	43,398
Loans	19,460	20,401
Off-balance sheet	12,922	12,779
Oil & Gas | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,878	1,902
Oil & Gas | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	40,099	42,077
Loans	13,079	13,343
Off-balance sheet	25,142	26,832
Asset Managers | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	10,819	7,733
Asset Managers | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	31,886	23,815
Loans	10,539	6,703
Off-balance sheet	10,528	9,379
Utilities | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	883	1,689
Utilities | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	29,622	30,853
Loans	7,183	5,294
Off-balance sheet	21,556	23,870
State & Municipal Govt | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,096	3,287
State & Municipal Govt | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	28,263	29,114
Loans	12,416	9,626
Off-balance sheet	13,751	16,201
Central Govt | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	14,235	13,240
Central Govt | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	20,408	17,968
Loans	3,964	2,000
Off-balance sheet	2,209	2,728
Transportation | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	751	1,575
Transportation | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	19,029	19,227
Loans	8,942	9,157
Off-balance sheet	9,336	8,495
Automotive | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,190	1,350
Automotive | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	16,635	13,864
Loans	4,943	4,473
Off-balance sheet	10,502	8,041
Chemicals & Plastics | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	271	369
Chemicals & Plastics | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	14,988	15,232
Loans	5,287	4,033
Off-balance sheet	9,430	10,830
Metals & Mining | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	439	607
Metals & Mining | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	13,419	14,049
Loans	4,350	4,622
Off-balance sheet	8,630	8,820
Insurance | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,382	1,992
Insurance | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	13,151	11,889
Loans	947	1,094
Off-balance sheet	8,822	8,803
Financial Markets Infrastructure | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,884	2,602
Financial Markets Infrastructure | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	8,732	7,973
Loans	347	724
Off-balance sheet	4,501	4,647
Securities Firms | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,913	1,424
Securities Firms | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	3,867	4,412
Loans	794	861
Off-balance sheet	1,160	2,127
All other | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,682	4,593
All other | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	144,428	149,117
Loans	109,267	109,889
Off-balance sheet	31,479	34,635
Loans held-for-sale and loans at fair value | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	4,515	3,965
Loans	$ 4,515	$ 3,965