Allowance for Credit Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for Credit Losses	$ (47)	$ (214)	$ (664)	$ (940)
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	19,140	19,354	19,140	19,354
Retained Loans, Evaluated at Formula-Based Impairment Methodology	643,996	641,547	643,996	641,547
Retained Loans, Purchased Credit-Impaired	56,748	62,626	56,748	62,626
Total Retained Loans	719,884	723,527	719,884	723,527	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	283	565	283	565
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	1,039,851	1,015,781	1,039,851	1,015,781
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	1,040,134	1,016,346	1,040,134	1,016,346	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			3,825	5,563
Valuation Allowances and Reserves, Recoveries			(697)	(898)
Allowance for Credit Losses, Provision for Loss, Net			3,128	4,665
Provision for Credit Losses			579	846
Allowance for Credit Losses, Adjustments, Net			(3)	1
Allowance for Credit Losses, Ending Balance	19,384	23,791	19,384	23,791
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	2,168	3,388	2,168	3,388
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	11,505	14,692	11,505	14,692
Allowance for Loan Losses, Purchased Credit-Impaired	5,711	5,711	5,711	5,711
Total Allowance for Credit Losses	19,384	23,791	19,384	23,791
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			85	94
Allowance for Credit Losses, Adjustments, Net			0	(3)
Allowance for Credit Losses, Ending Balance	753	764	753	764
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	79	181	79	181
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	674	583	674	583
Total Allowance for Credit Losses	753	764	753	764
Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net			142	97
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	3,546	1,558	3,546	1,558
Consumer, excluding credit card
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	14,251	11,614	14,251	11,614
Retained Loans, Evaluated at Formula-Based Impairment Methodology	216,401	225,821	216,401	225,821
Retained Loans, Purchased Credit-Impaired	56,736	62,611	56,736	62,611
Total Retained Loans	287,388	300,046	287,388	300,046	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	0	0
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	62,303	62,438	62,303	62,438
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	62,303	62,438	62,303	62,438
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			1,295	2,188
Valuation Allowances and Reserves, Recoveries			(231)	(268)
Allowance for Credit Losses, Provision for Loss, Net			1,064	1,920
Provision for Credit Losses			(531)	(423)
Allowance for Credit Losses, Adjustments, Net			(6)	(8)
Allowance for Credit Losses, Ending Balance	10,691	13,943	10,691	13,943
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	713	1,004	713	1,004
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	4,267	7,228	4,267	7,228
Allowance for Loan Losses, Purchased Credit-Impaired	5,711	5,711	5,711	5,711
Total Allowance for Credit Losses	10,691	13,943	10,691	13,943
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			1	0
Allowance for Credit Losses, Adjustments, Net			0	0
Allowance for Credit Losses, Ending Balance	8	7	8	7
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	0	0	0	0
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	8	7	8	7
Total Allowance for Credit Losses	8	7	8	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			132	51
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	3,152	887	3,152	887
Credit card
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	3,857	5,794	3,857	5,794
Retained Loans, Evaluated at Formula-Based Impairment Methodology	120,431	118,799	120,431	118,799
Retained Loans, Purchased Credit-Impaired	0	0	0	0
Total Retained Loans	124,288	124,593	124,288	124,593	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	0	0
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	532,359	534,267	532,359	534,267
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	532,359	534,267	532,359	534,267
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			2,414	3,210
Valuation Allowances and Reserves, Recoveries			(318)	(479)
Allowance for Credit Losses, Provision for Loss, Net			2,096	2,731
Provision for Credit Losses			1,046	1,231
Allowance for Credit Losses, Adjustments, Net			(6)	0
Allowance for Credit Losses, Ending Balance	4,445	5,499	4,445	5,499
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	1,227	1,977	1,227	1,977
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	3,218	3,522	3,218	3,522
Allowance for Loan Losses, Purchased Credit-Impaired	0	0	0	0
Total Allowance for Credit Losses	4,445	5,499	4,445	5,499
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	0	0
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	0	0	0	0
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	0	0	0	0
Total Allowance for Credit Losses	0	0	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	0	0
Wholesale
Loans by impairment methodology
Retained Loans, Evaluated at Asset-Specific Impairment Methodology	1,032	1,946	1,032	1,946
Retained Loans, Evaluated at Formula-Based Impairment Methodology	307,164	296,927	307,164	296,927
Retained Loans, Purchased Credit-Impaired	12	15	12	15
Total Retained Loans	308,208	298,888	308,208	298,888	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	283	565	283	565
Off Balance Sheet Lending-Related Financial Commitments, Contractual Amount, Evaluated at Formula-Based Impairment Methodology	445,189	419,076	445,189	419,076
Total Off-Balance Sheet Lending Related Financial Commitments, Contractual Amount	445,472	419,641	445,472	419,641
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			116	165
Valuation Allowances and Reserves, Recoveries			(148)	(151)
Allowance for Credit Losses, Provision for Loss, Net			(32)	14
Provision for Credit Losses			64	38
Allowance for Credit Losses, Adjustments, Net			9	9
Allowance for Credit Losses, Ending Balance	4,248	4,349	4,248	4,349
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance for Loan Losses, Evaluated at Asset-Specific Impairment Methodology	228	407	228	407
Allowance for Loan Losses, Evaluated at Formula-Based Impairment Methodology	4,020	3,942	4,020	3,942
Allowance for Loan Losses, Purchased Credit-Impaired	0	0	0	0
Total Allowance for Credit Losses	4,248	4,349	4,248	4,349
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			84	94
Allowance for Credit Losses, Adjustments, Net			0	(3)
Allowance for Credit Losses, Ending Balance	745	757	745	757
Allowance For Lending Related Commitments, by Impairment Methodology
Allowance For Lending-Related Commitments,Evaluated at Asset-Specific Impairment Methodology	79	181	79	181
Allowance For Lending-Related Commitments,Evaluated at Formula-Based Impairment Methodology	666	576	666	576
Total Allowance for Credit Losses	745	757	745	757
Wholesale | Impaired collateral dependent loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for Credit Losses, Provision for Loss, Net			10	46
Impaired Collateral Dependent Loans [Abstract]
Loans measured at fair value of collateral less cost to sell	$ 394	$ 671	$ 394	$ 671