Loans - Purchased Credit-Impaired Accretable Yields (Details) (Consumer, Excluding Credit Card, Purchased Credit-Impaired [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012 years	Dec. 31, 2011	Dec. 31, 2010
Consumer, Excluding Credit Card \| Purchased Credit-Impaired [Member]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Beginning Balance	$ 19,072	$ 19,097	$ 25,544
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	(2,491)	(2,767)	(3,232)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Changes in Interest Rates on Variable Rate Loans	(449)	(573)	(819)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications to Nonaccretable Difference	2,325	3,315	(2,396)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Ending Balance	$ 18,457	$ 19,072	$ 19,097
Accretable Yield Percentage	4.38%	4.33%	4.35%
Estimated Weighted-average Life of the Portfolio Over which Net Spread Will be Earned on a Declining Loan Balance	8

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 current period recognition due to accretion of the 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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- Definition

The change in the estimate of cash flows expected to be collected, after acquisition of a loan, which results in a decrease in accretable yield (for example, if it is probable that expected cash flows will be less than previously expected). This relates to loans not accounted for as a debt security, 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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