Sale of Accounts Receivable (Narrative) (Details) € in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 EUR (€)	Dec. 31, 2020 USD ($)
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Transfer of Financial Assets Accounted for as Sales, Fair Value of Derecognized Assets	$ 1,500,000,000		$ 1,500,000,000			$ 1,600,000,000
Proceeds from Sale of Other Receivables			34,200,000,000	$ 24,200,000,000
Proceeds from Collection of Retained Interest in Securitized Receivables			0	6,724,000,000
Loss on transfer of accounts receivables to purchasers	2,000,000	$ 2,000,000	8,000,000	7,000,000
Amount of receivables sold			36,700,000,000	$ 24,900,000,000
Pledged Assets, Not Separately Reported, Finance Receivables	1,100,000,000		1,100,000,000			400,000,000
Accounts Receivable Securitization Facility [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	2,100,000,000		2,100,000,000
First Purchasers [Member] | Accounts Receivable Securitization Facility [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,500,000,000		1,500,000,000			$ 1,200,000,000
Second Purchasers [Member] | Accounts Receivable Securitization Facility [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 600,000,000		$ 600,000,000		€ 0.5