Risk Management (Schedule of Largest Notional Amounts of the Positions to Buy or Sell Foreign Currency) (Details) - Foreign exchange contracts - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Long | British Pound
Derivative [Line Items]
Notional amount of foreign currency derivatives	$ 246,000,000	$ 62,000,000
Long | Euro
Derivative [Line Items]
Notional amount of foreign currency derivatives	122,000,000	99,000,000
Short | Chinese Renminbi
Derivative [Line Items]
Notional amount of foreign currency derivatives	108,000,000	114,000,000
Short | Brazilian Real
Derivative [Line Items]
Notional amount of foreign currency derivatives	56,000,000	44,000,000
Short | Australian Dollar
Derivative [Line Items]
Notional amount of foreign currency derivatives	$ 51,000,000	$ 60,000,000