Benefit Plans (Plan Asset Allocations) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 455,000,000	$ 402,000,000	$ 379,000,000
Percentage of Plan Assets	100.00%	100.00%
Foreign Plan [Member] | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	4.00%
Percentage of Plan Assets	4.61%	18.66%
Foreign Plan [Member] | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	93.00%
Percentage of Plan Assets	93.10%	78.35%
Foreign Plan [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,000,000	$ 3,000,000
Target Allocations	0.00%
Percentage of Plan Assets	0.44%	0.75%
Foreign Plan [Member] | Other
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	3.00%
Percentage of Plan Assets	1.85%	2.24%
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 1,127,000,000	$ 1,044,000,000	$ 1,021,000,000
Percentage of Plan Assets	100.00%	100.00%
UNITED STATES | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	33.00%
Percentage of Plan Assets	31.90%	50.96%
UNITED STATES | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	65.00%
Percentage of Plan Assets	64.53%	45.88%
UNITED STATES | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 36,000,000	$ 33,000,000
Target Allocations	2.00%
Percentage of Plan Assets	3.20%	3.16%
UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 4,000,000	$ 0
UNITED STATES | Other
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	0.00%
Percentage of Plan Assets	0.37%	0.00%
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 355,000,000	$ 300,000,000
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,091,000,000	1,011,000,000
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,000,000	0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	90,000,000	90,000,000
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	36,000,000	33,000,000
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	36,000,000	33,000,000
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	10,000,000	12,000,000
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,000,000	3,000,000
Fair Value, Inputs, Level 3 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0	$ 0