Sale of Accounts Receivable (Narrative) (Details) $ in Millions, € in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 EUR (€)	Dec. 31, 2019 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	$ 1,700		$ 1,700			$ 1,900
Transfer of Financial Assets Accounted for as Sales, Cash Proceeds Received for Assets Derecognized, Amount	1,400		1,400			1,400
Deferred Receivables Consideration	272		272			$ 446
Proceeds from Sale of Other Receivables			24,200	$ 25,100
Proceeds from Collection of Retained Interest in Securitized Receivables			6,724	9,527
Loss on transfer of accounts receivables to purchasers	2	$ 5	7	$ 14
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	1,800		1,800
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	1,200		1,200
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		$ 600		€ 0.5