Income Taxes - Open Tax Years (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Accrual for interest and penalties related to income tax matters	$ 25	$ 25
Minimum | United States – Federal
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2016
Minimum | United Kingdom
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2017
Minimum | Germany
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2012
Minimum | France
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2014
Minimum | Australia
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2013
Maximum | United States – Federal
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2018
Maximum | United Kingdom
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2018
Maximum | Germany
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2018
Maximum | France
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2018
Maximum | Australia
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2018