Loans - Impaired (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	$ 726,835,000,000	$ 718,997,000,000	$ 685,498,000,000
Consumer, Excluding Credit Card
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	292,620,000,000	308,427,000,000	327,464,000,000
Modified Loans Repurchased From U S Government Agencies Excluded From Troubled Debt Restructurings	7,500,000,000	4,300,000,000
Consumer, Excluding Credit Card | Minimum [Member]
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Number of Payments Under New Terms to Recognize Interest on Cash Basis	6
Consumer, Excluding Credit Card | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Days Past Due, 60 or More, with Notification of Bankruptcy Filing or Other Event [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Period Past Due, Credit Analysis Factors, Charge off Criteria	60 days
Consumer, Excluding Credit Card | Consumer Loan Excluding Credit Card [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	292,620,000,000	308,427,000,000
Consumer, Excluding Credit Card | Residential Real Estate [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Allowance for Loan and Lease Losses, Write-offs	747,000,000
Consumer, Excluding Credit Card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	10,100,000,000	8,320,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,145,000,000	768,000,000
Loans Receivable Held for Investment, Net of Deferred Income	151,896,000,000	163,660,000,000
Financing Receivable, Modifications, Recorded Investment	13,245,000,000	9,088,000,000	5,344,000,000
Impaired Financing Receivable, Recorded Investment	13,245,000,000	9,088,000,000
Impaired Financing Receivable, Related Allowance	591,000,000	591,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	18,555,000,000	12,444,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	10,941,000,000	7,750,000,000	4,542,000,000
Loans and Leases Receivable, Impaired, Troubled Debt Restructurings Not Having Yet Made Six Payments	2,900,000,000	886,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	490,000,000	323,000,000	216,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method	87,000,000	33,000,000	35,000,000
Consumer, Excluding Credit Card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member] | Days Past Due, 60 or More, with Notification of Bankruptcy Filing or Other Event [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Period Past Due, Credit Analysis Factors, Charge off Criteria	90 days
Consumer, Excluding Credit Card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	8,460,000,000	6,530,000,000
Impaired Financing Receivable, Recorded Investment	4,402,000,000	1,990,000,000
Consumer, Excluding Credit Card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Allowance for Loan and Lease Losses, Write-offs	747,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	2,700,000,000
Consumer, Excluding Credit Card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	1,700,000,000
Financing Receivable, Modifications, Recorded Investment	1,600,000,000
Consumer, Excluding Credit Card | Home Equity - Senior Lien [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	542,000,000	319,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	550,000,000	16,000,000
Loans Receivable Held for Investment, Net of Deferred Income	19,385,000,000	21,765,000,000
Financing Receivable, Modifications, Recorded Investment	1,092,000,000	335,000,000	226,000,000
Impaired Financing Receivable, Recorded Investment	1,092,000,000	335,000,000
Impaired Financing Receivable, Related Allowance	159,000,000	80,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	1,408,000,000	433,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	610,000,000	287,000,000	207,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	27,000,000	10,000,000	15,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method	12,000,000	1,000,000	1,000,000
Consumer, Excluding Credit Card | Home Equity - Senior Lien [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	931,000,000	495,000,000
Impaired Financing Receivable, Recorded Investment	607,000,000	77,000,000
Consumer, Excluding Credit Card | Home Equity - Senior Lien [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	596,000,000
Consumer, Excluding Credit Card | Home Equity - Senior Lien [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	450,000,000
Financing Receivable, Modifications, Recorded Investment	450,000,000
Consumer, Excluding Credit Card | Home Equity - Junior Lien [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	677,000,000	622,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	546,000,000	35,000,000
Loans Receivable Held for Investment, Net of Deferred Income	48,000,000,000	56,035,000,000
Financing Receivable, Modifications, Recorded Investment	1,223,000,000	657,000,000	283,000,000
Period Past Due, Credit Analysis Factors, Charge off Criteria	180 days
Impaired Financing Receivable, Recorded Investment	1,223,000,000	657,000,000
Impaired Financing Receivable, Related Allowance	188,000,000	141,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	2,352,000,000	994,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	848,000,000	521,000,000	266,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	42,000,000	18,000,000	10,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method	16,000,000	2,000,000	1,000,000
Consumer, Excluding Credit Card | Home Equity - Junior Lien [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	2,277,000,000	792,000,000
Impaired Financing Receivable, Recorded Investment	599,000,000	159,000,000
Consumer, Excluding Credit Card | Home Equity - Junior Lien [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	990,000,000
Consumer, Excluding Credit Card | Home Equity - Junior Lien [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	440,000,000
Financing Receivable, Modifications, Recorded Investment	448,000,000
Consumer, Excluding Credit Card | Prime Mortgages, Including Option ARMs [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	5,810,000,000	4,332,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,308,000,000	545,000,000
Loans Receivable Held for Investment, Net of Deferred Income	76,256,000,000	76,196,000,000
Financing Receivable, Modifications, Recorded Investment	7,118,000,000	4,877,000,000	2,084,000,000
Impaired Financing Receivable, Recorded Investment	7,118,000,000	4,877,000,000
Impaired Financing Receivable, Related Allowance	70,000,000	4,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	9,095,000,000	6,190,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	5,989,000,000	3,859,000,000	1,530,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	238,000,000	147,000,000	70,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method	28,000,000	14,000,000	14,000,000
Consumer, Excluding Credit Card | Prime Mortgages, Including Option ARMs [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	3,445,000,000	3,462,000,000
Impaired Financing Receivable, Recorded Investment	1,888,000,000	922,000,000
Consumer, Excluding Credit Card | Prime Mortgages, Including Option ARMs [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	500,000,000
Consumer, Excluding Credit Card | Prime Mortgages, Including Option ARMs [Member] | Regulatory Guidance Regarding Prime, including Option ARM, mortgages [Member]
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	713,000,000
Consumer, Excluding Credit Card | Prime Mortgages, Including Option ARMs [Member] | Regulatory Guidance Regarding Prime, including Option ARM, mortgages [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Financing Receivable, Modifications, Recorded Investment	465,000,000
Consumer, Excluding Credit Card | Subprime Mortgages [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	3,071,000,000	3,047,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	741,000,000	172,000,000
Loans Receivable Held for Investment, Net of Deferred Income	8,255,000,000	9,664,000,000
Financing Receivable, Modifications, Recorded Investment	3,812,000,000	3,219,000,000	2,751,000,000
Impaired Financing Receivable, Recorded Investment	3,812,000,000	3,219,000,000
Impaired Financing Receivable, Related Allowance	174,000,000	366,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	5,700,000,000	4,827,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	3,494,000,000	3,083,000,000	2,539,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	183,000,000	148,000,000	121,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method	31,000,000	16,000,000	19,000,000
Consumer, Excluding Credit Card | Subprime Mortgages [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	1,807,000,000	1,781,000,000
Impaired Financing Receivable, Recorded Investment	1,308,000,000	832,000,000
Consumer, Excluding Credit Card | Subprime Mortgages [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	379,000,000
Consumer, Excluding Credit Card | Subprime Mortgages [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	357,000,000
Financing Receivable, Modifications, Recorded Investment	245,000,000
Consumer, Excluding Credit Card | Other Consumer [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	621,000,000	801,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	72,000,000	3,000,000
Loans Receivable Held for Investment, Net of Deferred Income	80,987,000,000	79,221,000,000
Financing Receivable, Modifications, Recorded Investment	502,000,000	503,000,000	486,000,000
Impaired Financing Receivable, Recorded Investment	693,000,000	804,000,000
Impaired Financing Receivable, Related Allowance	138,000,000	237,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	883,000,000	948,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	733,000,000	852,000,000	802,000,000
Consumer, Excluding Credit Card | Other Consumer [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	714,000,000	881,000,000
Financing Receivable, Modifications, Recorded Investment	312,000,000	291,000,000
Impaired Financing Receivable, Recorded Investment	503,000,000	592,000,000
Consumer, Excluding Credit Card | Auto Loans [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	78,000,000	88,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	72,000,000	3,000,000
Loans Receivable Held for Investment, Net of Deferred Income	49,913,000,000	47,426,000,000
Financing Receivable, Modifications, Recorded Investment	150,000,000	88,000,000	91,000,000
Impaired Financing Receivable, Recorded Investment	150,000,000	91,000,000
Impaired Financing Receivable, Related Allowance	12,000,000	12,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	259,000,000	126,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	111,000,000	92,000,000	120,000,000
Consumer, Excluding Credit Card | Auto Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	163,000,000	118,000,000
Financing Receivable, Modifications, Recorded Investment	109,000,000	38,000,000
Impaired Financing Receivable, Recorded Investment	109,000,000	41,000,000
Consumer, Excluding Credit Card | Auto Loans [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Allowance for Loan and Lease Losses, Write-offs	53,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	146,000,000
Consumer, Excluding Credit Card | Auto Loans [Member] | Regulatory Guidance Regarding Chapter 7 Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	51,000,000
Financing Receivable, Modifications, Recorded Investment	72,000,000
Consumer, Excluding Credit Card | Business Banking Loans [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	543,000,000	713,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Loans Receivable Held for Investment, Net of Deferred Income	18,883,000,000	17,652,000,000
Financing Receivable, Modifications, Recorded Investment	352,000,000	415,000,000	395,000,000
Impaired Financing Receivable, Recorded Investment	543,000,000	713,000,000
Impaired Financing Receivable, Related Allowance	126,000,000	225,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	624,000,000	822,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	622,000,000	760,000,000	682,000,000
Consumer, Excluding Credit Card | Business Banking Loans [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	481,000,000	694,000,000
Financing Receivable, Modifications, Recorded Investment	203,000,000	253,000,000
Impaired Financing Receivable, Recorded Investment	394,000,000	551,000,000
Credit Card
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	127,993,000,000	132,175,000,000	135,524,000,000
Credit Card | Credit Card Loan [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	127,993,000,000	132,175,000,000
Financing Receivable, Modifications, Recorded Investment	4,189,000,000	6,075,000,000
Loans and Leases Receivable, Impaired, Reverted to Original Payment Terms Amount	573,000,000	1,139,000,000
Impaired Financing Receivable, Recorded Investment	4,762,000,000	7,214,000,000
Impaired Financing Receivable, Related Allowance	1,681,000,000	2,727,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	5,893,000,000	8,499,000,000	10,730,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method	308,000,000	463,000,000	605,000,000
Credit Card | Credit Card Loan [Member] | Completion of Short Term Modification [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans and Leases Receivable, Impaired, Reverted to Original Payment Terms Amount	232,000,000	377,000,000
Credit Card | Credit Card Loan [Member] | Noncompliance With Modified Terms [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans and Leases Receivable, Impaired, Reverted to Original Payment Terms Amount	341,000,000	762,000,000
Credit Card | Credit Card Loan [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	1,000,000	1,000,000
Wholesale
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	306,222,000,000	278,395,000,000	222,510,000,000
Wholesale | Wholesale Loan [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,091,000,000	1,959,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	384,000,000	590,000,000
Loans Receivable Held for Investment, Net of Deferred Income	306,222,000,000	278,395,000,000
Financing Receivable, Modifications, Recorded Investment	696,000,000	750,000,000	1,143,000,000
Impaired Financing Receivable, Recorded Investment	1,475,000,000	2,549,000,000
Impaired Financing Receivable, Related Allowance	319,000,000	516,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	1,923,000,000	3,917,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	1,960,000,000	3,860,000,000	5,949,000,000
Wholesale | Wholesale Loan [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	1,434,000,000	2,398,000,000
Financing Receivable, Modifications, Recorded Investment	636,000,000	578,000,000
Wholesale | Commercial and Industrial [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	588,000,000	828,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	173,000,000	177,000,000
Loans Receivable Held for Investment, Net of Deferred Income	109,865,000,000	94,215,000,000
Financing Receivable, Modifications, Recorded Investment	575,000,000	531,000,000	212,000,000
Impaired Financing Receivable, Recorded Investment	761,000,000	1,005,000,000
Impaired Financing Receivable, Related Allowance	205,000,000	276,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	957,000,000	1,705,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	873,000,000	1,309,000,000	1,655,000,000
Wholesale | Commercial and Industrial [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	708,000,000	889,000,000
Financing Receivable, Modifications, Recorded Investment	522,000,000	415,000,000
Wholesale | Wholesale Real Estate [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	375,000,000	621,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	133,000,000	292,000,000
Loans Receivable Held for Investment, Net of Deferred Income	60,740,000,000	54,684,000,000
Financing Receivable, Modifications, Recorded Investment	99,000,000	176,000,000	907,000,000
Impaired Financing Receivable, Recorded Investment	508,000,000	913,000,000
Impaired Financing Receivable, Related Allowance	82,000,000	148,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	626,000,000	1,124,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	784,000,000	1,813,000,000	3,101,000,000
Wholesale | Wholesale Real Estate [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	520,000,000	886,000,000
Financing Receivable, Modifications, Recorded Investment	92,000,000	128,000,000
Wholesale | Financial Institutions, Government Agencies and Other Wholesale [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Financing Receivable, Modifications, Recorded Investment	22,000,000	43,000,000	24,000,000
Wholesale | Financial Institutions, Government Agencies and Other Wholesale [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Financing Receivable, Modifications, Recorded Investment	22,000,000	35,000,000
Wholesale | Financial Institutions [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	6,000,000	21,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2,000,000	18,000,000
Loans Receivable Held for Investment, Net of Deferred Income	36,227,000,000	38,219,000,000
Impaired Financing Receivable, Recorded Investment	8,000,000	39,000,000
Impaired Financing Receivable, Related Allowance	2,000,000	5,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	22,000,000	63,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	17,000,000	84,000,000	304,000,000
Wholesale | Financial Institutions [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	8,000,000	37,000,000
Wholesale | Government Agencies [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	16,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Loans Receivable Held for Investment, Net of Deferred Income	9,544,000,000	7,819,000,000
Impaired Financing Receivable, Recorded Investment	0	16,000,000
Impaired Financing Receivable, Related Allowance	0	10,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	0	17,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	9,000,000	20,000,000	5,000,000
Wholesale | Government Agencies [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	0	16,000,000
Wholesale | Wholesale Other [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	122,000,000	473,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	76,000,000	103,000,000
Loans Receivable Held for Investment, Net of Deferred Income	89,846,000,000	83,458,000,000
Impaired Financing Receivable, Recorded Investment	198,000,000	576,000,000
Impaired Financing Receivable, Related Allowance	30,000,000	77,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance	318,000,000	1,008,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment	277,000,000	634,000,000	884,000,000
Wholesale | Wholesale Other [Member] | Nonaccrual [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Loans Receivable Held for Investment, Net of Deferred Income	$ 198,000,000	$ 570,000,000