Postretirement Benefits (Estimated Total Future Postretirement Benefit Payments, Net Of Participant Contributions And Estimated Future Medicare Part D Subsidy Receipts) (Details) - Other Postretirement Benefits Plan [Member] $ in Millions	Dec. 31, 2018 USD ($)
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Payments, year 1	$ 24
Benefit Payments, year 2	23
Benefit Payments, year 3	21
Benefit Payments, year 4	20
Benefit Payments, year 5	19
Benefit Payments, year 6-10	77
Subsidy Receipts, year 1	1
Subsidy Receipts, year 2	1
Subsidy Receipts, year 3	1
Subsidy Receipts, year 4	1
Subsidy Receipts, year 5	1
Subsidy Receipts, year 6-10	5
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Payments, year 1	1
Benefit Payments, year 2	1
Benefit Payments, year 3	1
Benefit Payments, year 4	1
Benefit Payments, year 5	1
Benefit Payments, year 6-10	$ 7