Loans (Details 14) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Credit risk profile of commercial loan
Total	$ 37,417	$ 33,649
Construction and other real estate [Member]
Credit risk profile of commercial loan
Total	7,977	7,860
Business banking and middle markets enterprises [Member]
Credit risk profile of commercial loan
Total	11,256	10,225
Global banking [Member]
Credit risk profile of commercial loan
Total	15,042	12,658
Other commercial [Member]
Credit risk profile of commercial loan
Total	3,142	2,906
Commercial Loan [Member]
Credit risk profile of commercial loan
Total	37,417	33,649
Commercial Loan [Member] | Investment Grade [Member]
Credit risk profile of commercial loan
Total	23,496	18,300
Commercial Loan [Member] | Non-Investment Grade [Member]
Credit risk profile of commercial loan
Total	13,921	15,349
Commercial Loan [Member] | Construction and other real estate [Member]
Credit risk profile of commercial loan
Total	7,977	7,860
Commercial Loan [Member] | Construction and other real estate [Member] | Investment Grade [Member]
Credit risk profile of commercial loan
Total	3,343	3,133
Commercial Loan [Member] | Construction and other real estate [Member] | Non-Investment Grade [Member]
Credit risk profile of commercial loan
Total	4,634	4,727
Commercial Loan [Member] | Business banking and middle markets enterprises [Member]
Credit risk profile of commercial loan
Total	11,256	10,225
Commercial Loan [Member] | Business banking and middle markets enterprises [Member] | Investment Grade [Member]
Credit risk profile of commercial loan
Total	5,608	4,612
Commercial Loan [Member] | Business banking and middle markets enterprises [Member] | Non-Investment Grade [Member]
Credit risk profile of commercial loan
Total	5,648	5,613
Commercial Loan [Member] | Global banking [Member]
Credit risk profile of commercial loan
Total	15,042	12,658
Commercial Loan [Member] | Global banking [Member] | Investment Grade [Member]
Credit risk profile of commercial loan
Total	13,333	9,712
Commercial Loan [Member] | Global banking [Member] | Non-Investment Grade [Member]
Credit risk profile of commercial loan
Total	1,709	2,946
Commercial Loan [Member] | Other commercial [Member]
Credit risk profile of commercial loan
Total	3,142	2,906
Commercial Loan [Member] | Other commercial [Member] | Investment Grade [Member]
Credit risk profile of commercial loan
Total	1,212	843
Commercial Loan [Member] | Other commercial [Member] | Non-Investment Grade [Member]
Credit risk profile of commercial loan
Total	$ 1,930	$ 2,063