Income Taxes - Tax Jurisdictions and Years Currently under Audit Exam (Details) $ in Millions	3 Months Ended
	Dec. 31, 2017 USD ($)
Income Tax Examination [Line Items]
Estimated benefit to tax expense	$ 25
Belgium | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2015
Belgium | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2016
Brazil | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2011
Brazil | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2012
CANADA | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2013
CANADA | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2014
CHINA | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2008
CHINA | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2016
France | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2010
France | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2016
Germany | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2007
Germany | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2015
JAPAN
Income Tax Examination [Line Items]
Tax years currently under audit exam	2016
SPAIN | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2010
SPAIN | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2014
SWITZERLAND | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2011
SWITZERLAND | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2014
United Kingdom | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2011
United Kingdom | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2014