Retirement Benefits (Schedule Of Defined Benefit Plan Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Operating income	$ (908)	$ (749)
Other net benefit credits	(66)	(60)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	18
Interest cost	118	122
Expected return on plan assets	(221)	(224)
Amortization of prior service cost	0	0
Recognized actuarial loss (gain)	37	40
Net periodic benefit (credit) cost	(56)	(44)
Curtailment gain (loss)	0	(1)
Settlement loss	0	1
Operating income	10	18
Other net benefit credits	(66)	(62)
Total (credit) cost	(56)	(44)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	1	1
Expected return on plan assets	0	0
Amortization of prior service cost	(1)	1
Recognized actuarial loss (gain)	0	0
Net periodic benefit (credit) cost	0	2
Curtailment gain (loss)	0	0
Settlement loss	0	0
Operating income	0	0
Other net benefit credits	0	2
Total (credit) cost	0	2
Domestic Plan | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	59	66
Expected return on plan assets	(89)	(89)
Amortization of prior service cost	0	0
Recognized actuarial loss (gain)	13	9
Net periodic benefit (credit) cost	(17)	(14)
Domestic Plan | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	0	0
Expected return on plan assets	0	0
Amortization of prior service cost	0	1
Recognized actuarial loss (gain)	0	0
Net periodic benefit (credit) cost	0	1
Foreign Plan | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	18
Interest cost	59	56
Expected return on plan assets	(132)	(135)
Amortization of prior service cost	0	0
Recognized actuarial loss (gain)	24	31
Net periodic benefit (credit) cost	(39)	(30)
Curtailment gain (loss)	0	(1)
Settlement loss	0	1
Total (credit) cost	(39)	(30)
Foreign Plan | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	1	1
Expected return on plan assets	0	0
Amortization of prior service cost	(1)	0
Recognized actuarial loss (gain)	0	0
Net periodic benefit (credit) cost	0	1
Curtailment gain (loss)	0	0
Settlement loss	0	0
Total (credit) cost	$ 0	$ 1