Financial Instruments - Summary of Notional Amount and Gross Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amounts	$ 11,734	$ 3,210
Derivatives Assets	193	17
Derivative Liabilities	121	18
Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	2,322	517
Derivatives Assets	15	1
Derivative Liabilities	13	2
Balance sheet items | Derivatives Not Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	6,357	2,693
Derivatives Assets	24	16
Derivative Liabilities	42	16
Balance sheet items | Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	0	38
Derivatives Assets	0	0
Derivative Liabilities	0	2
Forecasted transactions | Derivatives Not Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	945	0
Derivatives Assets	15	0
Derivative Liabilities	17	0
Forecasted transactions | Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	158	4
Derivatives Assets	2	1
Derivative Liabilities	3	0
Interest rate/Cross-currency interest rate swaps | Derivatives Not Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	2,110	0
Derivatives Assets	112	0
Derivative Liabilities	40	0
Commodity contracts | Derivatives Not Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	0	0
Derivatives Assets	27	0
Derivative Liabilities	9	0
Interest rate swaps | Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional Amounts	2,164	475
Derivatives Assets	13	0
Derivative Liabilities	10	$ 0
Prepaid Expenses and Other Current Assets
Derivative [Line Items]
Derivatives Assets	67
Other Noncurrent Assets
Derivative [Line Items]
Derivatives Assets	126
Other Current Liabilities
Derivative [Line Items]
Derivative Liabilities	78
Other Noncurrent Liabilities
Derivative [Line Items]
Derivative Liabilities	$ 43