Long-Term Debt (Schedule of Debt) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Due within one year	$ 17,438us-gaap_LongTermDebtCurrent	$ 17,172us-gaap_LongTermDebtCurrent
Due after one year	48,668us-gaap_LongTermDebtNoncurrent	51,848us-gaap_LongTermDebtNoncurrent
Derivative, Amount of Hedged Item	452us-gaap_DerivativeAmountOfHedgedItem	445us-gaap_DerivativeAmountOfHedgedItem
Long-term debt	66,558us-gaap_LongTermDebt	69,465us-gaap_LongTermDebt
Unsecured Debt [Member]
Debt Instrument [Line Items]
Due within one year	4,809	5,321
Due after one year	17,154	21,425
Derivative, Amount of Hedged Item	452	445
Long-term debt	22,415	27,191
Secured Debt [Member]
Debt Instrument [Line Items]
Due within one year	12,629	11,851
Due after one year	31,514	30,423
Derivative, Amount of Hedged Item	0	0
Long-term debt	$ 44,143	$ 42,274

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Amount of the hedged item as of the balance sheet date related to the derivative. For example, the hedged balance on a debt instrument.

+ References

No definition available.

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

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-Publisher FASB

-Name Accounting Standards Codification

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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-Publisher SEC

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-Number 210

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