Retirement Benefits (Net Periodic Pension Costs (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amortization of:
Curtailment gain	$ 0	$ (32)	$ 0
Settlement loss	26	0	1,917
U.S. Pension Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	182	193	370
Expected return on plan assets	(220)	(212)	(381)
Amortization of:
Unrecognized net loss	37	46	97
Unrecognized prior service benefit	0	0	0
Curtailment gain	0	0	0
Settlement loss	0	0	1,883
Net periodic cost (benefit)	(1)	27	1,969
Non U.S. Pension Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	11	12	15
Interest cost	55	66	80
Expected return on plan assets	(93)	(103)	(90)
Amortization of:
Unrecognized net loss	11	17	12
Unrecognized prior service benefit	0	(3)	(7)
Curtailment gain	0	(32)	0
Settlement loss	26	0	0
Net periodic cost (benefit)	10	(43)	10
Postretirement Health Care Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	2
Interest cost	4	8	10
Expected return on plan assets	(9)	(9)	(10)
Amortization of:
Unrecognized net loss	5	8	9
Unrecognized prior service benefit	(27)	(59)	(50)
Curtailment gain	0	0	0
Settlement loss	0	0	0
Net periodic cost (benefit)	$ (27)	$ (51)	$ (39)