Derivative Instruments and Hedging Activities - Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Other Noncurrent Assets [Member] | Designated as hedging instrument [member] | Interest rate swaps [member]
Derivative [Line Items]
Derivative asset	$ 48	$ 11
Other current assets [member] | Designated as hedging instrument [member] | Foreign exchange forward contracts [member]
Derivative [Line Items]
Derivative asset	1	0
Other current assets [member] | Not designated as hedging instrument [member] | Foreign exchange forward contracts [member]
Derivative [Line Items]
Derivative asset	1	4
Accounts payable, accrued expenses and other [member] | Designated as hedging instrument [member] | Foreign exchange forward contracts [member]
Derivative [Line Items]
Derivative liability	0	1
Accounts payable, accrued expenses and other [member] | Not designated as hedging instrument [member] | Foreign exchange forward contracts [member]
Derivative [Line Items]
Derivative liability	$ 2	$ 1