Loans - TDR Activity Rollforward (Details 4a) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Wholesale
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	$ 750	$ 1,143
New TDRs	70	49
Increases to Existing TDRs	1	2
Charge-offs post-modification	(11)	(148)
Principal payments, sales and other	(146)	(597)
Financing Receivables, Impaired, Troubled Debt Restructuring, Performing Loans Restructured at Market Rates but No Longer Reported as TDRs	23	78
Ending balance of TDRs	664	449
Wholesale | Commercial and industrial [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	531	212
New TDRs	4	9
Increases to Existing TDRs	1	2
Charge-offs post-modification	(9)	(6)
Principal payments, sales and other	(108)	(61)
Ending balance of TDRs	419	156
Wholesale | Real estate[Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	176	907
New TDRs	3	40
Increases to Existing TDRs	0	0
Charge-offs post-modification	(2)	(142)
Principal payments, sales and other	(29)	(535)
Ending balance of TDRs	148	270
Wholesale | Financial Institutions, Government Agencies and Other Wholesale [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	43	24
New TDRs	63	0
Increases to Existing TDRs	0	0
Charge-offs post-modification	0	0
Principal payments, sales and other	(9)	(1)
Ending balance of TDRs	97	23
Consumer Portfolio Segment | Residential real estate, excluding PCI [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	9,088	5,344
New TDRs	511	1,807
Charge-offs post-modification	(107)	(106)
Foreclosures and other liquidations	(69)	(37)
Principal payments, sales and other	(135)	(68)
Ending balance of TDRs	9,288	6,940
Consumer Portfolio Segment | Home Equity Senior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	335	226
New TDRs	12	37
Charge-offs post-modification	(5)	(3)
Foreclosures and other liquidations	0	0
Principal payments, sales and other	(4)	(3)
Ending balance of TDRs	338	257
Consumer Portfolio Segment | Home Equity Junior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	657	283
New TDRs	96	168
Charge-offs post-modification	(17)	(15)
Foreclosures and other liquidations	(3)	(3)
Principal payments, sales and other	(27)	(8)
Ending balance of TDRs	706	425
Consumer Portfolio Segment | Prime Mortgages, including option ARMs [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	4,877	2,084
New TDRs	281	1,260
Charge-offs post-modification	(34)	(23)
Foreclosures and other liquidations	(29)	(16)
Principal payments, sales and other	(77)	(36)
Ending balance of TDRs	5,018	3,269
Consumer Portfolio Segment | Subprime Mortgage [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	3,219	2,751
New TDRs	122	342
Charge-offs post-modification	(51)	(65)
Foreclosures and other liquidations	(37)	(18)
Principal payments, sales and other	(27)	(21)
Ending balance of TDRs	3,226	2,989
Consumer Portfolio Segment | Other Consumer [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	503	486
New TDRs	30	69
Charge-offs post-modification	(5)	(3)
Foreclosures and other liquidations	0	0
Principal payments, sales and other	(59)	(54)
Ending balance of TDRs	469	498
Consumer Portfolio Segment | Consumer Loans Auto Financing Receivable [Member]
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	88	91
New TDRs	17	13
Charge-offs post-modification	(2)	(2)
Foreclosures and other liquidations	0	0
Principal payments, sales and other	(12)	(12)
Ending balance of TDRs	91	90
Consumer Portfolio Segment | Consumer business banking
Loans Modified in TDRs [Roll Forward]
Beginning balance of TDRs	415	395
New TDRs	13	56
Charge-offs post-modification	(3)	(1)
Foreclosures and other liquidations	0	0
Principal payments, sales and other	(47)	(42)
Ending balance of TDRs	378	408
Permanent Modification [Member] | Consumer Portfolio Segment | Residential real estate, excluding PCI [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	8,826	6,387
Permanent Modification [Member] | Consumer Portfolio Segment | Home Equity Senior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	296	234
Permanent Modification [Member] | Consumer Portfolio Segment | Home Equity Junior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	695	409
Permanent Modification [Member] | Consumer Portfolio Segment | Prime Mortgages, including option ARMs [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	4,768	2,990
Permanent Modification [Member] | Consumer Portfolio Segment | Subprime Mortgage [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	3,067	2,754
Trial Modification [Member] | Consumer Portfolio Segment | Residential real estate, excluding PCI [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	462	553
Trial Modification [Member] | Consumer Portfolio Segment | Home Equity Senior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	42	23
Trial Modification [Member] | Consumer Portfolio Segment | Home Equity Junior Lien [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	11	16
Trial Modification [Member] | Consumer Portfolio Segment | Prime Mortgages, including option ARMs [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	250	279
Trial Modification [Member] | Consumer Portfolio Segment | Subprime Mortgage [Member]
Loans Modified in TDRs [Roll Forward]
Ending balance of TDRs	$ 159	$ 235