Pension And Other Postretirement Benefits (Benefit Obligations And Plan Assets Associated With Principal Benefit Plans) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Medicare subsidy receipts		$ 13	$ 16
U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.40%	3.80%
Long-term rate of compensation increase		5.75%	5.75%
Benefit obligation at January 1		$ 19,310	$ 19,960
Service cost		819	784	$ 810
Interest cost		721	798	793
Defined benefit plan, actuarial net (gains) losses		(957)	733
Benefits paid	[1],[2]	(1,715)	(2,964)
Amendments, divestments and other		(4)	(1)
Benefit obligation at December 31		18,174	19,310	19,960
Accumulated benefit obligation at December 31		$ 14,683	$ 15,557
Pension Benefits - Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.00%	2.80%
Long-term rate of compensation increase		4.30%	4.30%
Benefit obligation at January 1		$ 27,963	$ 25,196
Service cost		608	596	585
Interest cost		754	772	844
Defined benefit plan, actuarial net (gains) losses		(1,034)	250
Benefits paid	[1],[2]	(1,284)	(1,291)
Foreign exchange rate changes		(1,664)	2,484
Amendments, divestments and other		35	(44)
Benefit obligation at December 31		25,378	27,963	25,196
Accumulated benefit obligation at December 31		$ 23,350	$ 25,557
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.40%	3.80%
Long-term rate of compensation increase		5.75%	5.75%
Benefit obligation at January 1		$ 8,100	$ 7,800
Service cost		152	129	153
Interest cost		301	317	344
Defined benefit plan, actuarial net (gains) losses		(630)	231
Benefits paid	[1],[2]	(528)	(543)
Foreign exchange rate changes		(49)	40
Amendments, divestments and other		125	126
Benefit obligation at December 31		$ 7,471	$ 8,100	$ 7,800

[1] Benefit payments for funded and unfunded plans.

[2] For 2018 and 2017, other postretirement benefits paid are net of $13 million and $16 million of Medicare subsidy receipts, respectively.