Derivative Instruments - Impact on Statements of Income, Cash Flow Hedges (Details 2b) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flow hedge gains and losses [Abstract]
Loss on discontinuation of cash flow hedge due to forecasted wholesale deposits probable of not occurring			$ 25
Recognition of losses related to cash flow hedges in Income	(32)
Maximum length of time hedged in forecasted transactions	8 years
Cash Flow Hedging [Member]
Cash flow hedge gains and losses [Abstract]
Hedge ineffectiveness recorded directly in income	5	19	17
Total income statement impact	33	320	223
Cash Flow Hedging [Member] \| Interest Rate Contract [Member]
Cash flow hedge gains and losses [Abstract]
Derivatives - effective portion reclassified from AOCI to income	(3)	310	288
Hedge ineffectiveness recorded directly in income	5	19	20
Total income statement impact	2	329	308
Effective portion recorded in OCI	13	107	388
Total change in OCI for period	16	(203)	100
Cash Flow Hedging [Member] \| Foreign exchange
Cash flow hedge gains and losses [Abstract]
Derivatives - effective portion reclassified from AOCI to income	31	(9)	(82)
Hedge ineffectiveness recorded directly in income	0	0	(3)
Total income statement impact	31	(9)	(85)
Effective portion recorded in OCI	128	(57)	(141)
Total change in OCI for period	97	(48)	(59)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Cash flow hedge gains and losses [Abstract]
Total change in OCI for period	113	(251)	41
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Cash Flow Hedging [Member]
Cash flow hedge gains and losses [Abstract]
Derivatives - effective portion reclassified from AOCI to income	28	301	206
Effective portion recorded in OCI	141	50	247
Total change in OCI for period	$ 113	$ (251)	$ 41

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The amount of loss reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Before tax amount, net of reclassification adjustments, of the change in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Also includes an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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