Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Contributions to U.S. non qualified and non-U.S. Pension Plan	$ 51
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit credit	(2)	$ 125
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit credit	33	14
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit credit	18	$ (31)
Expected contribution during remainder of 2016	$ 166
Equity Funds \| United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan	64.00%
Actual asset allocation percentage of equity	62.00%
Fixed Income Funds \| United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan	36.00%
Actual asset allocation percentage of equity	38.00%
United Kingdom \| Equity Funds \| Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan	48.00%
Actual asset allocation percentage of equity	45.00%
United Kingdom \| Fixed Income Funds \| Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan	52.00%
Actual asset allocation percentage of equity	55.00%
United Kingdom \| Geographic Concentration Risk \| Non-U.S. Plans \| Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Concentration risk percentage	83.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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The increase in the fair value of plan assets from contributions made by the employer.

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The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Target allocation of investments of this type to total plan assets presented on a weighted average basis.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

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