Derivative Financial Instruments and Hedging Activities Income Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Maximum Length of Time Hedged in Cash Flow Hedge	2 years
Gain/(Loss) Recognized in Income	$ 1,561	$ 537	$ 736
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	(120)	72	407
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	124	(69)	(387)
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Foreign currency exchange contracts [Member]
Derivative [Line Items]
Gain/(Loss) Reclassified from AOCI to Income	537	(239)	78
Gain/(Loss) Recorded in OCI	770	123	(271)
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Interest rate contracts [Member]
Derivative [Line Items]
Net interest settlements and accruals excluded from the assessment of hedge effectiveness	367	370	304
Ineffectiveness	4	3	20
Not Designated as Hedging Instrument [Member] \| Foreign currency exchange contracts [Member]
Derivative [Line Items]
Gain/(Loss) Recognized in Income	257	425	261
Not Designated as Hedging Instrument [Member] \| Cross-currency interest rate swap contracts [Member]
Derivative [Line Items]
Gain/(Loss) Recognized in Income	398	100	161
Not Designated as Hedging Instrument [Member] \| Interest rate contracts [Member]
Derivative [Line Items]
Gain/(Loss) Recognized in Income	(9)	(58)	(41)
Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member]
Derivative [Line Items]
Gain/(Loss) Recognized in Income	$ 7	$ (64)	$ (47)

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
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-Publisher FASB
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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The net gain (loss) included in earnings for the period relating to components of the gain (loss) on interest rate fair value hedging instruments excluded from the assessment of fair value hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
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The net gain (loss) recognized in earnings during the period due to the ineffectiveness on interest rate fair value hedges.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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