Benefit Obligations (Schedule of Weighted Average Target Asset Allocations) (Details)	Dec. 31, 2017
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	100.00%
Domestic Plan [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	75.00%
Domestic Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	8.00%
Domestic Plan [Member] | Equity Securities International To Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	7.00%
Domestic Plan [Member] | Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	10.00%
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	100.00%
Foreign Plan [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	59.00%
Foreign Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	16.00%
Foreign Plan [Member] | Equity Securities International To Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	0.00%
Foreign Plan [Member] | Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average target asset allocations	25.00%