Financial Instruments and Fair Value Measurements, Pretax effect of derivative instruments charged directly to income (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	$ (53)	$ 10	$ (507)	$ (116)
Gain (loss) reclassified from AOCI to income	90	(89)	84	(110)
Gain (loss) recognized in income	49	55	238	160
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing	1	3
Amount of gain (loss) recognized in earnings on derivative amount excluded for effectiveness testing	1	5	8	15
Pretax effect of the periodic receipt of fixed interest and payment of variable interest		1	(3)	7
Minimum [Member]
Derivative Instruments, gain (loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing			(1)	0
Pretax effect of the periodic receipt of fixed interest and payment of variable interest	(1)
Maximum [Member]
Derivative Instruments, gain (loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income on derivative amount excluded for effectiveness testing			0	1
Pretax effect of the periodic receipt of fixed interest and payment of variable interest	0
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	7	0	(34)
Gain (loss) reclassified from AOCI to income	0	(10)	0	(18)
Gain (loss) recognized in income	0	0	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	8	(10)	6	28
Gain (loss) reclassified from AOCI to income	0	8	0	12
Gain (loss) recognized in income	0	0	0	0
Derivatives: [Member] \| Designated as hedges: [Member] \| Foreign currency [Member] \| Interest expense [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	(125)	141	(47)	192
Gain (loss) reclassified from AOCI to income	89	(86)	81	(99)
Gain (loss) recognized in income	8	18	38	50
Derivatives: [Member] \| Designated as hedges: [Member] \| Interest rate contract [Member] \| Interest expense [Member]
Derivative Instruments, gain (loss) [Line Items]
Gain (loss) recognized in AOCI	102	(163)	(430)	(342)
Gain (loss) reclassified from AOCI to income	1	(1)	3	(5)
Gain (loss) recognized in income	1	23	91	96
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	0	0
Gain (loss) reclassified from AOCI to income	0	0	0	0
Gain (loss) recognized in income	(1)	(1)	4	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	0	0
Gain (loss) reclassified from AOCI to income	0	0	0	0
Gain (loss) recognized in income	42	1	116	(18)
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	0	0
Gain (loss) reclassified from AOCI to income	0	0	0	0
Gain (loss) recognized in income	(1)	14	(11)	30
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	(38)	35	(36)	40
Gain (loss) reclassified from AOCI to income	0	0	0	0
Gain (loss) recognized in income	$ 0	$ 0	$ 0	$ 0

Net amount of accrued interest related to the hedged item and interest rate swap derivative.

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Amount of gain (loss) from excluded component of derivative hedge, recognized in earnings. Excludes recognition under systematic and rational method.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Amount, before tax and adjustments, of gain (loss) from increase (decrease) in value of excluded component of derivative designated and qualifying as hedge. Adjustments include, but are not limited to, reclassifications for sale and settlement, and amounts recognized under systematic and rational method.

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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