Loans - Contractual Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	$ 22,276
2014	5,848
2015	4,410
2016	5,239
2017	5,615
Thereafter	19,870
Total	63,258		51,867	49,809
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	44,150		33,649
Commercial Loan [Member] | Construction and Other Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	3,564
2014	869
2015	768
2016	993
2017	1,041
Thereafter	1,222
Total	8,457		7,860	8,228
Commercial Loan [Member] | Business Banking and Middle Markets Enterprises [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	5,108
2014	1,346
2015	1,184
2016	1,559
2017	1,603
Thereafter	1,808
Total	12,608		10,225	7,945
Commercial Loan [Member] | Global Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	10,025
2014	1,670
2015	1,514
2016	1,743
2017	2,070
Thereafter	2,987
Total	20,009		12,658	10,745
Commercial Loan [Member] | Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	1,251
2014	327
2015	288
2016	379
2017	390
Thereafter	441
Total	3,076		2,906	3,085
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	19,108		18,218
Consumer Loans [Member] | Home Equity Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	870	[1]
2014	432	[1]
2015	265	[1]
2016	166	[1]
2017	107	[1]
Thereafter	484	[1]
Total	2,324	[1]	2,563	3,820
Consumer Loans [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	909
2014	361
2015	378
2016	393
2017	402
Thereafter	12,928
Total	15,371		14,113	13,697
Consumer Loans [Member] | Credit Card Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	0	[2]
2014	815	[2]
2015	0	[2]
2016	0	[2]
2017	0	[2]
Thereafter	0	[2]
Total	815	[2]	828	1,250
Consumer Loans [Member] | Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2013	549
2014	28
2015	13
2016	6
2017	2
Thereafter	0
Total	$ 598		$ 714	$ 1,039

[1] Home equity mortgages maturities reflect estimates based on historical payment patterns.

[2] As credit card receivables do not have stated maturities, the table reflects estimates based on historical payment patterns.