Financial Instruments (Fair Value Derivative Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Equity Contract, Warrant [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	$ 949
Equity Contract, Preemptive Rights [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	393
Net Investment Hedging [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	1,405	$ 41
Fair Value of Liabilities	0	4
Net Investment Hedging [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	63	41
Fair Value of Liabilities	0	4
Net Investment Hedging [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	48	37
Net Investment Hedging [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	15	4
Net Investment Hedging [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Liabilities	0	0
Net Investment Hedging [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Liabilities	0	4
Net Investment Hedging [Member] | Equity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	1,342	0
Net Investment Hedging [Member] | Equity Contract, Warrant [Member] | Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	949	0
Net Investment Hedging [Member] | Equity Contract, Preemptive Rights [Member] | Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Value of Assets	$ 393	$ 0