Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions				3 Months Ended				9 Months Ended
	Sep. 01, 2015	Aug. 01, 2015	Aug. 01, 2014	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jan. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in funded status of plan	$ (64)
Contributions to U.S. non qualified and non-U.S. Pension Plan								$ 138
United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in projected benefit obligation	$ (298)
Discount rate										4.30%
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit credit				$ (1)	$ 125	$ (4)		121	$ (12)
Gain (loss) due to curtailments				0		0		0	0
Non-U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in projected benefit obligation			$ 147
Effect of plan amendment on funded status											$ (137)
Net periodic benefit credit				13		17		42	83
Gain (loss) due to curtailments				(4)		0	$ 65	(4)	65
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit credit				(21)		(14)		(83)	6
Gain (loss) due to curtailments				$ (4)		$ 0		(4)	$ 65
Expected contribution during remainder of 2015								$ 59
Equity Funds [Member] | United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan								64.00%
Actual asset allocation percentage of equity				62.00%				62.00%
Fixed Income Funds [Member] | United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan								36.00%
Actual asset allocation percentage of equity				38.00%				38.00%
United Kingdom [Member] | Equity Funds [Member] | Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan								48.00%
Actual asset allocation percentage of equity				45.00%				45.00%
United Kingdom [Member] | Fixed Income Funds [Member] | Non-U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation U.S. Plan								52.00%
Actual asset allocation percentage of equity				55.00%				55.00%
United Kingdom [Member] | Geographic Concentration Risk [Member] | Non-U.S. Plans [Member] | Non-U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Concentration risk percentage								83.00%
IRELAND | Non-U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in projected benefit obligation		$ 59
Increase (decrease) in funded status of plan		$ (26)
Discount rate		1.80%								2.30%
Weighted Average [Member] | United States Pension and Postretirement Benefit Plan of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.67%