Income Taxes (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) assessment	Sep. 30, 2018	Sep. 30, 2019 USD ($) assessment	Sep. 30, 2018
Income Tax Contingency [Line Items]
Effective income tax rate	18.90%	15.20%	19.40%	14.30%
Brazilian Federal Revenue Service [Member]
Income Tax Contingency [Line Items]
Number of separate tax assessments | assessment	3		3
Income tax assessment	$ 101		$ 101
Income tax assessment - Interest and Penalties	295		295
Argentine Tax Authorities [Member]
Income Tax Contingency [Line Items]
Income tax assessment	15		15
Income tax assessment - Interest and Penalties	52		52
Estimated Additional Tax Assessment	33		33
Additional income tax assessment - Interest and Penalties	43		43
Tax and Customs Administration, Netherlands [Member]
Income Tax Contingency [Line Items]
Income tax assessment	88		88
Additional income tax assessment - Interest and Penalties	$ 32		$ 32