Financial Instruments and Fair Value Measurements, Pretax effect of derivative instruments charged directly to income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	$ (349)	$ 8
Gain (loss) reclassified from AOCI to income	(53)	(44)
Gain (loss) recognized in income	96	7
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing		2
Amount of gain (loss) recognized in earnings on derivative amount excluded for effectiveness testing	4	5
Pretax effect of the periodic receipt of fixed interest and payment of variable interest	2	3
Minimum [Member]
Derivative Instruments, gain (loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing	0
Maximum [Member]
Derivative Instruments, gain (loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing	1
Derivatives: [Member] | Designated as hedges: [Member] | Commodities [Member] | Sales and other operating revenues [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	0	(50)
Gain (loss) reclassified from AOCI to income	0	(5)
Gain (loss) recognized in income	0	0
Derivatives: [Member] | Designated as hedges: [Member] | Commodities [Member] | Cost of sales [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	0	46
Gain (loss) reclassified from AOCI to income	0	4
Gain (loss) recognized in income	0	0
Derivatives: [Member] | Designated as hedges: [Member] | Foreign currency [Member] | Other income (expense), net; Interest expense [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	164	70
Gain (loss) reclassified from AOCI to income	(53)	(39)
Gain (loss) recognized in income	16	17
Derivatives: [Member] | Designated as hedges: [Member] | Interest rate contract [Member] | Interest expense [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	(535)	(74)
Gain (loss) reclassified from AOCI to income	0	(4)
Gain (loss) recognized in income	96	(34)
Derivatives: [Member] | Not designated as hedges: [Member] | Commodities [Member] | Sales and other operating revenues [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	0	0
Gain (loss) reclassified from AOCI to income	0	0
Gain (loss) recognized in income	(9)	2
Derivatives: [Member] | Not designated as hedges: [Member] | Commodities [Member] | Cost of sales [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	0	0
Gain (loss) reclassified from AOCI to income	0	0
Gain (loss) recognized in income	(3)	3
Derivatives: [Member] | Not designated as hedges: [Member] | Foreign currency [Member] | Other income (expense), net [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	0	0
Gain (loss) reclassified from AOCI to income	0	0
Gain (loss) recognized in income	(4)	19
Non-derivatives: [Member] | Designated as hedges: [Member] | Long-term debt [Member] | Other income (expense), net [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	22	16
Gain (loss) reclassified from AOCI to income	0	0
Gain (loss) recognized in income	$ 0	$ 0