Debt (Debt) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	$ 11,841	$ 11,937
Debt, Current	197	221
Long-term Debt, Excluding Current Maturities	11,644	11,716
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	3,409	3,406
Loans Payable [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	2,642	3,277
Corporate Debt Securities [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	2,407	1,789
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	1,643	1,715
Secured Debt [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	1,559	1,565
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	$ 181	$ 185

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

+ 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 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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