Fair Value (Quantitative Information) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)
Fair Value Inputs Quantitative Information [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ (199)	$ (102)	$ 63	$ 14
Interest Rate Contract [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	(269)	(184)	(140)	(182)
Foreign Exchange Contract [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	99	94	199	194
Cross currency derivatives [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	(29)	(11)	0	0
Commodity Contract [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ 0	$ (1)	$ 4	$ 2
Argentina, Pesos | Foreign Exchange Contract [Member] | Minimum [Member]
Fair Value Derivative Assets Liabilities Measured On Recurring Basis Unobservable Inputs [Abstract]
Derivative, Forward Exchange Rate	0.97
Argentina, Pesos | Foreign Exchange Contract [Member] | Maximum [Member]
Fair Value Derivative Assets Liabilities Measured On Recurring Basis Unobservable Inputs [Abstract]
Derivative, Forward Exchange Rate	6.67
Argentina, Pesos | Foreign Exchange Contract [Member] | Weighted Average [Member]
Fair Value Derivative Assets Liabilities Measured On Recurring Basis Unobservable Inputs [Abstract]
Derivative, Forward Exchange Rate	3.38
Measurement Input, Entity Credit Risk [Member] | Interest Rate Contract [Member] | Minimum [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	1.80%
Measurement Input, Entity Credit Risk [Member] | Interest Rate Contract [Member] | Maximum [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	6.30%
Measurement Input, Entity Credit Risk [Member] | Interest Rate Contract [Member] | Weighted Average [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	6.10%
Measurement Input, Entity Credit Risk [Member] | Cross currency derivatives [Member] | Minimum [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	4.60%
Measurement Input, Entity Credit Risk [Member] | Cross currency derivatives [Member] | Maximum [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	4.60%
Measurement Input, Entity Credit Risk [Member] | Cross currency derivatives [Member] | Weighted Average [Member]
Fair Value Inputs Quantitative Information [Line Items]
Fair Value Measurement Inputs, Nonrecurring	4.60%