Sale of Accounts Receivable (Narrative) (Details) $ in Millions, € in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 EUR (€)	Dec. 31, 2018 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	$ 2,000		$ 2,000			$ 1,900
Transfer of Financial Assets Accounted for as Sales, Cash Proceeds Received for Assets Derecognized, Amount	1,700		1,700			1,500
Deferred Receivables Consideration	330		330			$ 379
Proceeds from Sale of Other Receivables			25,100	$ 26,300
Proceeds from Collection of Retained Interest in Securitized Receivables			9,527	8,804
Loss on transfer of accounts receivables to purchasers	5	$ 4	14	$ 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	1,300		1,300
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	$ 500		$ 500		€ 0.5