Purchased Credit Impaired Loans, Accretable Yield (Details) (USD $) In Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2009
Change in accretable yield related to PCI loans [Abstract]
Total, beginning of period	$ 15,881	$ 16,714	$ 14,559	$ 10,447
Accretion into interest income	(556)	(1,102)	(2,392)	(2,601)
Accretion into noninterest income due to sales	(31)	(186)	(43)	(5)
Reclassification from nonaccretable difference for loans with improving credit-related cash flows	95	210	3,399	441
Changes in expected cash flows that do not affect nonaccretable difference	(518)	(765)	1,191	6,277
Total, end of Period	$ 14,871	$ 14,871	$ 16,714	$ 14,559

The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The change in the estimate of cash flows expected to be collected, after acquisition of loans, which results in an increase in accretable yield (for example, if actual cash flows are significantly greater than previously expected). This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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