Retirement Benefits (Reconciliation of Net Actuarial Loss) (Details) (Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
U.S. Pension Benefits [Member]
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	$ (974)	$ (1,887)
Recognized as component of net periodic benefit cost	112	208
Liability experience	(955)	541
Asset experience	68	164
Total amount recognized as change in plan assets and benefit obligations	(887)	705
Ending balance, December 31	(1,749)	(974)
Non- U.S Pension Benefits [Member]
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	(3,010)	(3,309)
Recognized as component of net periodic benefit cost	131	108
Effect of settlement	0	0
Liability experience	(1,619)	53
Asset experience	1,112	111
Plan amendments	(14)	0
Total amount recognized as change in plan assets and benefit obligations	(521)	164
Exchange rate adjustments	185	27
Ending balance, December 31	(3,215)	(3,010)
U.S. Postretirement Benefits [Member]
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	13	(2)
Recognized as component of net periodic benefit cost	(2)	0
Liability experience	(21)	15
Asset experience	12	0
Total amount recognized as change in plan assets and benefit obligations	(9)	15
Ending balance, December 31	2	13
Foreign Postretirement Benefit Plan, Defined Benefit [Member]
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	(16)	(27)
Recognized as component of net periodic benefit cost	1	2
Effect of settlement	0	0
Liability experience	1	8
Asset experience	0	0
Plan amendments	0	0
Total amount recognized as change in plan assets and benefit obligations	1	8
Exchange rate adjustments	0	1
Ending balance, December 31	$ (14)	$ (16)