Allowance for Credit Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for Credit Losses	$ (617)	$ (726)
Allowance for Credit Losses, Ending Balance	20,780
Allowance For Lending Related Commitments, by Impairment Methodology
Total Allowance for Credit Losses	20,780
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	19,778	18,641
Retained Loans, Evaluated at Formula-Based Impairment Methodology	644,305	630,174
Retained Loans, Purchased Credit-Impaired	58,446	64,083
Total Retained Loans	722,529	712,898	726,835
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Asset-Specific Impairment Methodology	244	756
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	1,033,366	996,747
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	1,033,610	997,503	1,027,988
Allowance for Loans and Leases Receivable
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	21,936	27,609
Allowance for Credit Losses, Write-offs	2,034	2,853
Valuation Allowances and Reserves, Recoveries	(309)	(466)
Allowance for Credit Losses, Provision for Loss, Net	1,725	2,387
Provision for Credit Losses	569	646
Allowance for Credit Losses, Adjustments, Net	0	3
Allowance for Credit Losses, Ending Balance	20,780	25,871
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	2,433	3,610
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	12,636	16,550
Allowance for Loan Losses, Purchased Credit-Impaired	5,711	5,711
Total Allowance for Credit Losses	20,780	25,871
Allowance For Lending Related Commitments
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	668	673
Provision for Credit Losses	48	80
Allowance for Credit Losses, Adjustments, Net	0	(3)
Allowance for Credit Losses, Ending Balance	716	750
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	82	187
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	634	563
Total Allowance for Credit Losses	716	750
Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net	84	53
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	3,585	1,639
Consumer, excluding credit card
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Ending Balance	11,645
Allowance For Lending Related Commitments, by Impairment Methodology
Total Allowance for Credit Losses	11,645
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	14,189	10,059
Retained Loans, Evaluated at Formula-Based Impairment Methodology	217,456	230,650
Retained Loans, Purchased Credit-Impaired	58,437	64,061
Total Retained Loans	290,082	304,770	292,620
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Asset-Specific Impairment Methodology	0	0
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	60,874	63,121
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	60,874	63,121
Consumer, excluding credit card | Allowance for Loans and Leases Receivable
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	12,292	16,294
Allowance for Credit Losses, Write-offs	720	1,134
Valuation Allowances and Reserves, Recoveries	(112)	(138)
Allowance for Credit Losses, Provision for Loss, Net	608	996
Provision for Credit Losses	(37)	2
Allowance for Credit Losses, Adjustments, Net	(2)	(3)
Allowance for Credit Losses, Ending Balance	11,645	15,297
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	771	760
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	5,163	8,826
Allowance for Loan Losses, Purchased Credit-Impaired	5,711	5,711
Total Allowance for Credit Losses	11,645	15,297
Consumer, excluding credit card | Allowance For Lending Related Commitments
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	7	7
Provision for Credit Losses	0	(1)
Allowance for Credit Losses, Adjustments, Net	0	1
Allowance for Credit Losses, Ending Balance	7	7
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	0	0
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	7	7
Total Allowance for Credit Losses	7	7
Consumer, excluding credit card | Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net	78	29
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	3,153	849
Credit card
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Ending Balance	4,998
Allowance For Lending Related Commitments, by Impairment Methodology
Total Allowance for Credit Losses	4,998
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	4,287	6,524
Retained Loans, Evaluated at Formula-Based Impairment Methodology	117,578	117,951
Retained Loans, Purchased Credit-Impaired	0	0
Total Retained Loans	121,865	124,475	127,993
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Asset-Specific Impairment Methodology	0	0
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	537,455	533,318
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	537,455	533,318
Credit card | Allowance for Loans and Leases Receivable
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	5,501	6,999
Allowance for Credit Losses, Write-offs	1,248	1,627
Valuation Allowances and Reserves, Recoveries	(166)	(241)
Allowance for Credit Losses, Provision for Loss, Net	1,082	1,386
Provision for Credit Losses	582	636
Allowance for Credit Losses, Adjustments, Net	(3)	2
Allowance for Credit Losses, Ending Balance	4,998	6,251
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	1,434	2,402
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	3,564	3,849
Allowance for Loan Losses, Purchased Credit-Impaired	0	0
Total Allowance for Credit Losses	4,998	6,251
Credit card | Allowance For Lending Related Commitments
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	0	0
Provision for Credit Losses	0	0
Allowance for Credit Losses, Adjustments, Net	0	0
Allowance for Credit Losses, Ending Balance	0	0
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	0	0
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	0	0
Total Allowance for Credit Losses	0	0
Credit card | Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net	0	0
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	0	0
Wholesale
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Ending Balance	4,137
Allowance For Lending Related Commitments, by Impairment Methodology
Total Allowance for Credit Losses	4,137
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	1,302	2,058
Retained Loans, Evaluated at Formula-Based Impairment Methodology	309,271	281,573
Retained Loans, Purchased Credit-Impaired	9	22
Total Retained Loans	310,582	283,653	306,222
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Asset-Specific Impairment Methodology	244	756
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	435,037	400,308
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	435,281	401,064
Wholesale | Allowance for Loans and Leases Receivable
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	4,143	4,316
Allowance for Credit Losses, Write-offs	66	92
Valuation Allowances and Reserves, Recoveries	(31)	(87)
Allowance for Credit Losses, Provision for Loss, Net	35	5
Provision for Credit Losses	24	8
Allowance for Credit Losses, Adjustments, Net	5	4
Allowance for Credit Losses, Ending Balance	4,137	4,323
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	228	448
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	3,909	3,875
Allowance for Loan Losses, Purchased Credit-Impaired	0	0
Total Allowance for Credit Losses	4,137	4,323
Wholesale | Allowance For Lending Related Commitments
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Beginning Balance	661	666
Provision for Credit Losses	48	81
Allowance for Credit Losses, Adjustments, Net	0	(4)
Allowance for Credit Losses, Ending Balance	709	743
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	82	187
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	627	556
Total Allowance for Credit Losses	709	743
Wholesale | Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net	6	24
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	$ 432	$ 790