Derivative Financial Instruments, Outstanding Forward Contracts By Currency (Details) - Foreign Currency Forward Contracts [Member] $ in Millions	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Notional amount	$ 415
U.S. Dollar [Member]
Derivative [Line Items]
Notional amount	204
Canadian Dollar [Member]
Derivative [Line Items]
Notional amount	123
Euro [Member]
Derivative [Line Items]
Notional amount	67
United Arab Emirates, Dirhams
Derivative [Line Items]
Notional amount	12
British Pound [Member]
Derivative [Line Items]
Notional amount	$ 9