Asset Quality (Details 6) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consumer Credit Exposure Credit Risk Profile by Regulatory Classifications
Credit risk profile based on payment	$ 49,575	$ 50,107
Residential, Prime, Financing Receivable [Member]
Consumer Credit Exposure Credit Risk Profile by Regulatory Classifications
Credit risk profile based on payment	11,710	12,024
Pass [Member] | Residential, Prime, Financing Receivable [Member]
Consumer Credit Exposure Credit Risk Profile by Regulatory Classifications
Credit risk profile based on payment	11,471	11,765
Special Mention [Member] | Residential, Prime, Financing Receivable [Member]
Consumer Credit Exposure Credit Risk Profile by Regulatory Classifications
Credit risk profile based on payment	0	0
Substandard [Member] | Residential, Prime, Financing Receivable [Member]
Consumer Credit Exposure Credit Risk Profile by Regulatory Classifications
Credit risk profile based on payment	$ 239	$ 259