Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Gross charge-offs/Write-offs of PCI loans	$ 47	$ 55
Provision for credit losses	1,824	959
Loans by impairment methodology
Asset-specific			$ 13,079		$ 14,009
Formula-based			791,369		697,602
PCI			39,747		45,360
Total retained loans			844,195	$ 832,792	756,971
Lending-related commitments by impairment methodology
Asset-specific			722		131
Formula-based			959,712		949,035
Total lending-related commitments			960,434	940,395	949,166
Impaired collateral-dependent loans
Allowance for Loan and Lease Losses [Roll Forward]
Net charge-offs/(recoveries)	22	17
Impaired collateral-dependent loans
Loans measured at fair value of collateral less cost to sell			2,898		3,181
Allowance for loan losses
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,555	14,185
Gross charge-offs/Write-offs of PCI loans	1,357	1,352
Gross recoveries	(247)	(300)
Net charge-offs/(recoveries)	1,110	1,052
Provision for credit losses	1,596	988
Other	0	(1)
Ending balance	13,994	14,065
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Asset-specific			1,363		1,110
Formula-based			9,936		9,685
PCI			2,695		3,270
Total allowance for loan losses	13,555	14,185	13,994	13,555	14,065
Allowance for lending-related commitments
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	786	622
Provision for credit losses	228	(29)
Ending balance	1,014	593
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Allowance for lending-related commitments by impairment methodology, asset-specific			192		55
Allowance for lending-related commitments by impairment methodology, formula-based			822		538
Total allowance for loan losses	786	622	1,014	786	593
Consumer, excluding credit card
Allowance for Loan and Lease Losses [Roll Forward]
Gross charge-offs/Write-offs of PCI loans	47	55
Loans by impairment methodology
Asset-specific			9,468		11,414
Formula-based			304,660		248,147
PCI			39,743		45,356
Total retained loans			353,871	344,355	304,917
Lending-related commitments by impairment methodology
Asset-specific			0		0
Formula-based			60,744		60,151
Total lending-related commitments			60,744		60,151
Consumer, excluding credit card | Impaired collateral-dependent loans
Allowance for Loan and Lease Losses [Roll Forward]
Net charge-offs/(recoveries)	21	16
Impaired collateral-dependent loans
Loans measured at fair value of collateral less cost to sell			2,514		2,912
Consumer, excluding credit card | Allowance for loan losses
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,806	7,050
Gross charge-offs/Write-offs of PCI loans	365	440
Gross recoveries	(145)	(176)
Net charge-offs/(recoveries)	220	264
Provision for credit losses	221	141
Other	0	0
Ending balance	5,760	6,872
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Asset-specific			371		537
Formula-based			2,694		3,065
PCI			2,695		3,270
Total allowance for loan losses	5,806	7,050	5,760	5,806	6,872
Consumer, excluding credit card | Allowance for lending-related commitments
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14	13
Provision for credit losses	0	1
Ending balance	14	14
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Allowance for lending-related commitments by impairment methodology, asset-specific			0		0
Allowance for lending-related commitments by impairment methodology, formula-based			14		14
Total allowance for loan losses	14	13	14	14	14
Credit card
Allowance for Loan and Lease Losses [Roll Forward]
Gross charge-offs/Write-offs of PCI loans	0	0
Loans by impairment methodology
Asset-specific			1,381		1,852
Formula-based			124,631		118,983
PCI			0		0
Total retained loans			126,012	131,387	120,835
Lending-related commitments by impairment methodology
Asset-specific			0		0
Formula-based			532,224		533,511
Total lending-related commitments			532,224		533,511
Credit card | Impaired collateral-dependent loans
Allowance for Loan and Lease Losses [Roll Forward]
Net charge-offs/(recoveries)	0	0
Impaired collateral-dependent loans
Loans measured at fair value of collateral less cost to sell			0		0
Credit card | Allowance for loan losses
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,434	3,439
Gross charge-offs/Write-offs of PCI loans	923	883
Gross recoveries	(93)	(94)
Net charge-offs/(recoveries)	830	789
Provision for credit losses	830	789
Other	0	(5)
Ending balance	3,434	3,434
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Asset-specific			427		458
Formula-based			3,007		2,976
PCI			0		0
Total allowance for loan losses	3,434	3,439	3,434	3,434	3,434
Credit card | Allowance for lending-related commitments
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0
Provision for credit losses	0	0
Ending balance	0	0
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Allowance for lending-related commitments by impairment methodology, asset-specific			0		0
Allowance for lending-related commitments by impairment methodology, formula-based			0		0
Total allowance for loan losses	0	0	0	0	0
Wholesale
Allowance for Loan and Lease Losses [Roll Forward]
Gross charge-offs/Write-offs of PCI loans	0	0
Loans by impairment methodology
Asset-specific			2,230		743
Formula-based			362,078		330,472
PCI			4		4
Total retained loans			364,312	357,050	331,219
Lending-related commitments by impairment methodology
Asset-specific			722		131
Formula-based			366,744		355,373
Total lending-related commitments			367,466		355,504
Wholesale | Impaired collateral-dependent loans
Allowance for Loan and Lease Losses [Roll Forward]
Net charge-offs/(recoveries)	1	1
Impaired collateral-dependent loans
Loans measured at fair value of collateral less cost to sell			384		269
Wholesale | Allowance for loan losses
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,315	3,696
Gross charge-offs/Write-offs of PCI loans	69	29
Gross recoveries	(9)	(30)
Net charge-offs/(recoveries)	60	(1)
Provision for credit losses	545	58
Other	0	4
Ending balance	4,800	3,759
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Asset-specific			565		115
Formula-based			4,235		3,644
PCI			0		0
Total allowance for loan losses	4,315	3,696	4,800	4,315	3,759
Wholesale | Allowance for lending-related commitments
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	772	609
Provision for credit losses	228	(30)
Ending balance	1,000	579
Allowance For Lending Related Commitments, by Impairment Methodology [Abstract]
Allowance for lending-related commitments by impairment methodology, asset-specific			192		55
Allowance for lending-related commitments by impairment methodology, formula-based			808		524
Total allowance for loan losses	$ 772	$ 609	$ 1,000	$ 772	$ 579