Loans (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	$ 1,546		$ 2,273
Days Past Due, 30-89 days	617		813
Days Past Due, 90 + days	1,168		1,356
Total Past Due	3,331		4,442
Current	52,733		47,425
Total loans	56,064	[1]	51,867	[1]	49,612
Commercial loans [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	1,260		1,935
Days Past Due, 30-89 days	92		207
Days Past Due, 90 + days	199		397
Total Past Due	1,551		2,539
Current	35,866		31,110
Total loans	37,417		33,649
Commercial loans [Member] | Construction and other real estate [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	100		72
Days Past Due, 30-89 days	38		31
Days Past Due, 90 + days	114		231
Total Past Due	252		334
Current	7,725		7,526
Total loans	7,977		7,860		7,911
Commercial loans [Member] | Business banking and middle markets enterprises [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	496		615
Days Past Due, 30-89 days	37		58
Days Past Due, 90 + days	51		71
Total Past Due	584		744
Current	10,672		9,481
Total loans	11,256		10,225		8,631
Commercial loans [Member] | Global banking [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	110		898
Days Past Due, 30-89 days			34
Days Past Due, 90 + days	8		74
Total Past Due	118		1,006
Current	14,924		11,652
Total loans	15,042		12,658		10,603
Commercial loans [Member] | Other commercial [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	554		350
Days Past Due, 30-89 days	17		84
Days Past Due, 90 + days	26		21
Total Past Due	597		455
Current	2,545		2,451
Total loans	3,142		2,906		2,648
Consumer loans [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	286		338
Days Past Due, 30-89 days	525		606
Days Past Due, 90 + days	969		959
Total Past Due	1,780		1,903
Current	16,867		16,315
Total loans	18,647		18,218
Consumer loans [Member] | HELOC and home equity mortgages [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	145		181
Days Past Due, 30-89 days	40		54
Days Past Due, 90 + days	77		89
Total Past Due	262		324
Current	2,193		2,239
Total loans	2,455		2,563		3,607
Consumer loans [Member] | Other residential mortgages [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	100		109
Days Past Due, 30-89 days	465		526
Days Past Due, 90 + days	844		815
Total Past Due	1,409		1,450
Current	13,349		12,663
Total loans	14,758		14,113
Consumer loans [Member] | Credit cards [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	31		37
Days Past Due, 30-89 days	15		20
Days Past Due, 90 + days	17		20
Total Past Due	63		77
Current	720		751
Total loans	783		828		1,187
Consumer loans [Member] | Other consumer [Member]
Summary of Past Due Status of Loans
Days Past Due, 1-29 days	10		11
Days Past Due, 30-89 days	5		6
Days Past Due, 90 + days	31		35
Total Past Due	46		52
Current	605		662
Total loans	$ 651		$ 714		$ 925

[1] The following table summarizes assets and liabilities related to variable interest entities ("VIEs") as of June 30, 2012 and December 31, 2011 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation.