Benefit Plans (Accumulated Benefit Obligation) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 376	$ 433
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	89	109
Accumulated benefit obligation	79	97
Fair value of plan assets	33	33
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	220	238
Fair value of plan assets	150	154
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	1,101	1,236
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	1,118	1,257
Accumulated benefit obligation	1,101	1,236
Fair value of plan assets	1,026	1,127
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	1,118	1,257
Fair value of plan assets	$ 1,026	$ 1,127