Fair Value Measurements Derivative Designation and Hedging Relationship (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative, Notional Amount	$ 12,326	$ 5,923
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	5,880	2,671
Net Investment Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	1,483	0
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	3,962	3,252
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 1,000	$ 0