Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	$ 976,702	$ 940,395	$ 950,997
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	677,681
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	134,169
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	143,699
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	21,153
Off-balance sheet lending-related financial commitments, carrying value	1,519	1,213
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Unfunded commitments investments private equity funds third party	48	50
Unfunded commitments investments other equity investments	1,000	871
Investments entities that calculate net asset value per share, unfunded commitments	34	73
Wholesale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	368,014	366,399	$ 366,881
Warranty Reserves
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Allowance for lending-related commitments	133	148
Total consumer
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	608,688	573,996
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	589,282
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	4,713
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	1,330
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	13,363
Off-balance sheet lending-related financial commitments, carrying value	26	14
Consumer, excluding credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	54,797	58,478
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	35,391
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	4,713
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	1,330
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	13,363
Off-balance sheet lending-related financial commitments, carrying value	26	14
Home equity
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	21,714	22,756
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	4,247
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	3,578
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	1,035
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	12,854
Off-balance sheet lending-related financial commitments, carrying value	12	0
Residential mortgage
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	11,745	12,992
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	11,745
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	0
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	0
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	0
Off-balance sheet lending-related financial commitments, carrying value	0	0
Auto
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	8,468	10,237
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	7,807
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	461
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	173
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	27
Off-balance sheet lending-related financial commitments, carrying value	2	2
Business banking
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	12,733	12,351
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	11,485
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	673
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	122
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	453
Off-balance sheet lending-related financial commitments, carrying value	12	12
Student and other
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	137	142
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	107
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	1
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	0
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	29
Off-balance sheet lending-related financial commitments, carrying value	0	0
Credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	553,891	515,518
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	553,891
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	0
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	0
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	0
Off-balance sheet lending-related financial commitments, carrying value	0	0
Total wholesale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	368,014	366,399
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	88,399
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	129,456
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	142,369
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	7,790
Off-balance sheet lending-related financial commitments, carrying value	$ 1,493	$ 1,199
Total wholesale | Wholesale | Total U.S.
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Off balance sheet lending related financial commitments	79.00%	77.00%
Other unfunded commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	$ 328,497	$ 323,325
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	69,307
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	116,716
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	135,663
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	6,811
Off-balance sheet lending-related financial commitments, carrying value	905	649
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Risk participations for other unfunded commitments to extend credit	328	385
Standby letters of credit and other financial guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	35,947	39,133
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	15,738
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	12,654
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	6,577
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	978
Off-balance sheet lending-related financial commitments, carrying value	586	548
Guarantee liability	441	427
Allowance for lending-related commitments	145	121
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Risk participations for standby letters of credit and other financial guarantees	11,100	11,200
Other letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, contractual amount	3,570	3,941
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in less than one year	3,354
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between one and three years	86
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring between three and five years	129
Off-balance sheet lending-related financial commitments, Contractual amount, Expiring in more than five years	1
Off-balance sheet lending-related financial commitments, carrying value	2	2
Guarantee liability	0	0
Allowance for lending-related commitments	2	2
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Risk participations for other letters of credit	265	341
Securities lending indemnification agreements and guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	137,209	183,329
Other guarantees and commitments, Contractual amount, Expiring in less than one year	137,209
Other guarantees and commitments, Contractual amount, Expiring between one and three years	0
Other guarantees and commitments, Contractual amount, Expiring between three and five years	0
Other guarantees and commitments, Contractual amount, Expiring in more than five years	0
Guarantee liability	0	0
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Indemnification agreement securities lending guarantees collateral held in support of	143,200	190,600
Derivatives qualifying as guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	51,966	53,784
Other guarantees and commitments, Contractual amount, Expiring in less than one year	1,061
Other guarantees and commitments, Contractual amount, Expiring between one and three years	450
Other guarantees and commitments, Contractual amount, Expiring between three and five years	10,930
Other guarantees and commitments, Contractual amount, Expiring in more than five years	39,525
Guarantee liability	80	222
Unsettled reverse repurchase and securities borrowing agreements
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	50,722	42,482
Other guarantees and commitments, Contractual amount, Expiring in less than one year	50,722
Other guarantees and commitments, Contractual amount, Expiring between one and three years	0
Other guarantees and commitments, Contractual amount, Expiring between three and five years	0
Other guarantees and commitments, Contractual amount, Expiring in more than five years	0
Guarantee liability	0	0
Unsettled repurchase and securities lending agreements [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	26,948	21,798
Other guarantees and commitments, Contractual amount, Expiring in less than one year	26,948
Guarantee liability	0	0
Loans sold with recourse
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan sale and securitization-related indemnifications, Contractual amount	2,730	4,274
Loan sale and securitization-related indemnifications, Carrying value	64	82
Other guarantees and commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	5,715	5,580
Other guarantees and commitments, Contractual amount, Expiring in less than one year	383
Other guarantees and commitments, Contractual amount, Expiring between one and three years	2,662
Other guarantees and commitments, Contractual amount, Expiring between three and five years	1,017
Other guarantees and commitments, Contractual amount, Expiring in more than five years	1,653
Guarantee liability	(118)	(94)
Letters of credit hedged by derivative transactions
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, contractual amount	$ 4,600	$ 4,600
Days Past Due, 60 or More | Credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Line of credit close criteria, period past due	60 days