Sale Of Equipment Installment Receivables (Finance Receivables Repurchased) (Details) - Finance Receivables [Member] - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Changes In Other Assets [Line Items]
Fair value of repurchased receivables		$ 0	$ 567	$ 1,481	$ 1,281
Carrying value of deferred purchase price		0	507	1,393	1,147
Gain (Loss) on repurchases	[1]	$ 0	$ 60	$ 88	$ 134

[1] These gains (losses) are included in “Selling, general and administrative” in the consolidated statements of income.