Financial Instruments: (Details 3) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012 item	Dec. 31, 2011
Financial Instruments:
Derivative instruments with credit-risk related contingent features	$ 109	$ 131
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	1,228	1,300
Fair value of total derivative instruments, Liabilities	2,771	2,415
Maximum spread on credit default swap agreements before full overnight collateralization is required (in basis points)	250
Liabilities included in master netting arrangements	245	324
Total collateral received, derivatives	376	466
Non-cash collateral received and not recorded on the Statement of Financial Position	28
Amount recognized in accounts payable for the obligation to return cash collateral	376	466
Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	1,027	1,190
Fair value of total derivative instruments, Liabilities	340	428
Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	201	110
Fair value of total derivative instruments, Liabilities	59	103
Prepaid expenses and other current assets \| Interest rate contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	51	50
Prepaid expenses and other current assets \| Foreign exchange contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	184	407
Prepaid expenses and other current assets \| Foreign exchange contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	172	82
Prepaid expenses and other current assets \| Equity contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	11	7
Investments and sundry assets \| Interest rate contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	775	733
Investments and sundry assets \| Foreign exchange contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	17
Investments and sundry assets \| Foreign exchange contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Assets	18	21
Other accrued expenses and liabilities \| Foreign exchange contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	275	273
Other accrued expenses and liabilities \| Foreign exchange contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	38	84
Other accrued expenses and liabilities \| Equity contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	11	8
Other liabilities. \| Foreign exchange contracts \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	65	155
Other liabilities. \| Foreign exchange contracts \| Derivative instruments not designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	10	11
Long term debt. \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	1,729	1,884
Short term debt \| Derivative instruments designated as hedging instruments
Fair Values of Derivative Instruments
Fair value of total derivative instruments, Liabilities	$ 643

The credit default swap spread which, if exceeded, would trigger contingent features of these agreements.

No definition available.

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- Definition

The amount of non-cash collateral received, primarily U.S. Treasury securities, and is not recorded on the Statement of Financial Position.

+ References

No definition available.

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- Definition

The fair value, as of the date of each statement of financial position presented, of accounts payable which are collateral received for the repayment of the related debt obligation, and that are reclassified and separately reported in the statement of financial position.

+ References

No definition available.

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- Definition

The amount of the obligation to return cash collateral under master netting arrangements that have not been offset against net derivative instrument positions.

+ References

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- Definition

Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-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.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph a

-Clause 1

-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.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

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- Definition

Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

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- Definition

The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy was not offset against the right to reclaim cash collateral under a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FIN39-1

-Paragraph 10B

-Subparagraph a

-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 aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph b

-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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