Financial Instruments - Derivatives (Details) € in Millions, ¥ in Millions, ¥ in Millions, £ in Millions, kr in Millions, $ in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($) t	Jun. 30, 2018 JPY (¥)	Jun. 30, 2018 CNY (¥)	Jun. 30, 2018 SEK (kr)	Jun. 30, 2018 EUR (€)	Jun. 30, 2018 MXN ($)	Jun. 30, 2018 GBP (£)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 JPY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 SEK (kr)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 MXN ($)	Dec. 31, 2017 GBP (£)
Commodity contracts | Maturity December 2018
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | t	151.0
Brazil, Brazil Real | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives | €					€ 1.9							€ 1.1
United Kingdom, Pounds | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives	$ 5.8				15.9			$ 0.0				0.0
China, Yuan Renminbi | Foreign currency | Maturity September 2018
Derivative [Line Items]
Notional amount of currency derivatives	11.6							36.0
China, Yuan Renminbi | Foreign currency | Maturity June 2018
Derivative [Line Items]
Notional amount of currency derivatives | €					0.0							18.6
Euro Member Countries, Euro | Cross Currency Interest Rate Contract [Member] | Maturity September 2020
Derivative [Line Items]
Notional amount of currency derivatives	206.2
Euro Member Countries, Euro | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives		¥ 525.3	¥ 37.0				£ 2.0		¥ 1,311.3	¥ 85.0				£ 3.9
Euro Member Countries, Euro | Foreign currency | Maturity June 2019
Derivative [Line Items]
Notional amount of currency derivatives | kr				kr 267.4							kr 267.4
Euro Member Countries, Euro | Foreign currency | Maturity March 2019
Derivative [Line Items]
Notional amount of currency derivatives	24.7							56.5
Japan, Yen | Cross Currency Interest Rate Contract [Member] | Maturity February 2023
Derivative [Line Items]
Notional amount of currency derivatives	10,977.5
Japan, Yen | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives	1.4		¥ 44.0					0.0		¥ 0.0
Korea (South), Won | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives	29.8	¥ 213.5			0.8			$ 11.2	¥ 619.0			3.1
Sweden, Kronor | Foreign currency | Maturity January 2020
Derivative [Line Items]
Notional amount of currency derivatives | €					83.1							109.7
United States of America, Dollars | Cross Currency Interest Rate Contract [Member] | Maturity September 2020
Derivative [Line Items]
Notional amount of currency derivatives	250.0
United States of America, Dollars | Cross Currency Interest Rate Contract [Member] | Maturity February 2023
Derivative [Line Items]
Notional amount of currency derivatives	$ 100.0
United States of America, Dollars | Foreign currency | Maturity December 2018
Derivative [Line Items]
Notional amount of currency derivatives					€ 0.0	$ 264.9						€ 42.0	$ 0.0