Retirement Benefits (Summary of changes in the fair value of the plans’ Level 3 assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	$ 1,329	$ 1,245
Purchases	275	311
Sales	(263)	(251)
Unrealized Gain/(Loss)	254	(46)
Realized Gain/(Loss)	(194)	61
Exchange Rate Impact	29	10
Transfers in/(out) and Other	0	(1)
Fair Value, Asset Value, Ending	1,430	1,329
Private equity/partnerships [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	779	746
Purchases	86	119
Sales	(79)	(80)
Unrealized Gain/(Loss)	138	(83)
Realized Gain/(Loss)	(113)	70
Exchange Rate Impact	13	7
Transfers in/(out) and Other	0	0
Fair Value, Asset Value, Ending	824	779
Real estate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	319	293
Purchases	11	0
Sales	(3)	0
Unrealized Gain/(Loss)	104	22
Realized Gain/(Loss)	(86)	(1)
Exchange Rate Impact	12	5
Transfers in/(out) and Other	0	0
Fair Value, Asset Value, Ending	357	319
Other investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	202	177
Purchases	17	32
Sales	(24)	(13)
Unrealized Gain/(Loss)	11	6
Realized Gain/(Loss)	6	2
Exchange Rate Impact	4	(2)
Transfers in/(out) and Other	0	0
Fair Value, Asset Value, Ending	216	202
Insurance group annuity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	20	20
Purchases	160	151
Sales	(157)	(150)
Unrealized Gain/(Loss)	1	8
Realized Gain/(Loss)	(1)	(9)
Exchange Rate Impact	0	0
Transfers in/(out) and Other	0	0
Fair Value, Asset Value, Ending	23	20
Corporate stocks [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	8	1
Purchases	1	8
Sales	0	0
Unrealized Gain/(Loss)	0	(1)
Realized Gain/(Loss)	0	0
Exchange Rate Impact	0	0
Transfers in/(out) and Other	0	0
Fair Value, Asset Value, Ending	9	8
Corporate Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset Value, Beginning	1	8
Purchases	0	1
Sales	0	(8)
Unrealized Gain/(Loss)	0	2
Realized Gain/(Loss)	0	(1)
Exchange Rate Impact	0	0
Transfers in/(out) and Other	0	(1)
Fair Value, Asset Value, Ending	$ 1	$ 1

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Translation Adjustment

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of gain (loss) recognized in earnings, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) recognized in other comprehensive income, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents [net] transfers in to and out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(3)

-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.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-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.

+ Details

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Balance Type:	debit
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