Retirement Benefits (Reconciliation of Net Actuarial Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S. Pension Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	$ 0	$ 0
Non-U.S. Pension Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	(24)	(37)
U.S. Postretirement Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	12	(12)
Non-U.S. Postretirement Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	0	0
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) | U.S. Pension Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	(1,749)	(974)
Recognized as component of net periodic benefit cost	146	112
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	0	0
Liability experience	392	(955)
Asset experience	(543)	68
Total amount recognized as change in plan assets and benefit obligations	(151)	(887)
Ending balance, December 31	(1,754)	(1,749)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) | Non-U.S. Pension Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	(3,215)	(3,010)
Recognized as component of net periodic benefit cost	125	131
Effect of settlement	2	0
Liability experience	432	(1,619)
Asset experience	(417)	1,112
Plan amendments	(20)	(14)
Total amount recognized as change in plan assets and benefit obligations	(5)	(521)
Exchange rate adjustments	206	185
Ending balance, December 31	(2,887)	(3,215)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) | U.S. Postretirement Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	2	13
Recognized as component of net periodic benefit cost	(2)	(2)
Defined Benefit Plan, Fair Value Of Plan Assets, Other Changes	8	0
Liability experience	5	(21)
Asset experience	0	12
Total amount recognized as change in plan assets and benefit obligations	5	(9)
Ending balance, December 31	13	2
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) | Non-U.S. Postretirement Benefits
Reconciliation of unrecognized net actuarial gain loss [Roll Forward]
Beginning balance	(14)	(16)
Recognized as component of net periodic benefit cost	1	1
Effect of settlement	0	0
Liability experience	6	1
Asset experience	0	0
Plan amendments	0	0
Total amount recognized as change in plan assets and benefit obligations	6	1
Exchange rate adjustments	1	0
Ending balance, December 31	$ (6)	$ (14)