Off-balance sheet lending-related financial instruments, guarantees and other commitments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	$ 940,786		$ 950,997	$ 1,057,204
Off-balance sheet lending-related financial commitments, Carrying value	1,175		1,176
Allowance for lending-related commitments	184	$ 231	275	391	$ 436	$ 681
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Standby letters of credit, unissued commitments	45,100		45,600
Unfunded commitments investments private equity funds third party	57		147
Unfunded commitments investments other equity investments	1,400		961
Investments entities that calculate net asset value per share, unfunded commitments	53		150
Commitments to noninvestment-grade counterparties in connection with leveraged finance activities	30,300		23,400
Maximum
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Secured clearance advance facility maximum outstanding commitment	10,900		12,600
Wholesale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	354,348			$ 470,991
Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	661,243
Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	115,770
Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	146,076
Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	17,697
Consumer Loan
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	586,438		584,116
Off-balance sheet lending-related financial commitments, Carrying value	14		13
Consumer Loan | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	564,014
Consumer Loan | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	11,065
Consumer Loan | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	1,883
Consumer Loan | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	9,476
Total consumer, excluding credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	60,005		58,153
Off-balance sheet lending-related financial commitments, Carrying value	14		13
Total consumer, excluding credit card | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	37,581
Total consumer, excluding credit card | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	11,065
Total consumer, excluding credit card | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	1,883
Total consumer, excluding credit card | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	9,476
Home equity | Senior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	10,861		11,807
Off-balance sheet lending-related financial commitments, Carrying value	0		0
Home equity | Junior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	12,387		14,859
Off-balance sheet lending-related financial commitments, Carrying value	0		0
Home equity | Expires in 1 year or less | Senior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	1,632
Home equity | Expires in 1 year or less | Junior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	2,604
Home equity | Expires after 1 year through 3 years | Senior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4,082
Home equity | Expires after 1 year through 3 years | Junior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4,782
Home equity | Expires after 3 years through 5 years | Senior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	835
Home equity | Expires after 3 years through 5 years | Junior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	793
Home equity | Expires after 5 years | Senior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4,312
Home equity | Expires after 5 years | Junior lien
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4,208
Mortgage | Warranty Reserves
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Allowance for lending-related commitments	184		275
Mortgage | Prime
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	13,959		8,579
Off-balance sheet lending-related financial commitments, Carrying value	0		0
Mortgage | Expires in 1 year or less | Prime
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	13,959
Mortgage | Expires after 1 year through 3 years | Prime
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Mortgage | Expires after 3 years through 5 years | Prime
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Mortgage | Expires after 5 years | Prime
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Auto
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	9,986		10,462
Off-balance sheet lending-related financial commitments, Carrying value	2		2
Auto | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	8,380
Auto | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	1,416
Auto | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	165
Auto | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	25
Business banking
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	12,358		11,894
Off-balance sheet lending-related financial commitments, Carrying value	12		11
Business banking | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	10,998
Business banking | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	781
Business banking | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	90
Business banking | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	489
Student and other
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	454		552
Off-balance sheet lending-related financial commitments, Carrying value	0		0
Student and other | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	8
Student and other | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4
Student and other | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Student and other | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	442
Credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	526,433		525,963
Off-balance sheet lending-related financial commitments, Carrying value	0		0
Credit card | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	526,433
Credit card | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Credit card | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Credit card | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Total wholesale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	354,348		366,881
Off-balance sheet lending-related financial commitments, Carrying value	$ 1,161		$ 1,163
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, percent	77.00%		73.00%
Total wholesale | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	$ 97,229
Total wholesale | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	104,705
Total wholesale | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	144,193
Total wholesale | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	8,221
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	265,073		$ 272,676
Off-balance sheet lending-related financial commitments, Carrying value	386		374
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Risk participations for other unfunded commitments to extend credit	321		243
Credit enhancements and bond and commercial paper liquidity commitments to US states and municipalities hospitals and other not for profit entities	13,000		14,800
Other unfunded commitments to extend credit | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	70,201
Other unfunded commitments to extend credit | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	77,449
Other unfunded commitments to extend credit | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	110,713
Other unfunded commitments to extend credit | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	6,710
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	85,268		89,874
Off-balance sheet lending-related financial commitments, Carrying value	774		788
Allowance for lending-related commitments	334		234
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	11,700		13,000
Credit enhancements and bond and commercial paper liquidity commitments to US states and municipalities hospitals and other not for profit entities	10,000		13,300
Standby letters of credit and other financial guarantees | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	23,666
Standby letters of credit and other financial guarantees | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	26,670
Standby letters of credit and other financial guarantees | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	33,421
Standby letters of credit and other financial guarantees | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	1,511
Other letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	4,007		4,331
Off-balance sheet lending-related financial commitments, Carrying value	1		1
Allowance for lending-related commitments	1		1
Off balance sheet lending related financial instruments guarantees and other commitments - supplemental information [Abstract]
Risk participations for other letters of credit	409		469
Other letters of credit | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	3,362
Other letters of credit | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	586
Other letters of credit | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	59
Other letters of credit | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet lending-related financial commitments, Contractual amount	0
Securities lending indemnification agreements and guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	184,227		171,059
Guarantor obligations, Carrying value	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	190,300		177,100
Securities lending indemnification agreements and guarantees | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	184,227
Securities lending indemnification agreements and guarantees | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Securities lending indemnification agreements and guarantees | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Securities lending indemnification agreements and guarantees | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Derivatives qualifying as guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	52,189		53,589
Guarantor obligations, Carrying value	258		80
Derivatives qualifying as guarantees | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	1,421
Derivatives qualifying as guarantees | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	441
Derivatives qualifying as guarantees | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	11,337
Derivatives qualifying as guarantees | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	38,990
Unsettled reverse repurchase and securities borrowing agreements
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	56,525		40,993
Guarantor obligations, Carrying value	0		0
Unsettled reverse repurchase and securities borrowing agreements | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	56,525
Unsettled reverse repurchase and securities borrowing agreements | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Unsettled reverse repurchase and securities borrowing agreements | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Unsettled reverse repurchase and securities borrowing agreements | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	0
Loans sold with recourse
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan sale and securitization-related indemnifications, Contractual amount	4,685		6,063
Loan sale and securitization-related indemnifications, Carrying value	89		102
Other guarantees and commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	6,810		5,720
Guarantor obligations, Carrying value	(101)		(121)
Other guarantees and commitments | Expires in 1 year or less
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	1,429
Other guarantees and commitments | Expires after 1 year through 3 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	1,556
Other guarantees and commitments | Expires after 3 years through 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	2,206
Other guarantees and commitments | Expires after 5 years
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Other guarantees and commitments, Contractual amount	1,619
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		$ 4,500
Days Past Due, 60 or More [Member] | Credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Line of credit close criteria, period past due	60 days