Sale Of Equipment Installment Receivables (Finance Receivables Repurchased) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of repurchased receivables		$ 268	$ 0	$ 926	$ 1,481
Carrying value of deferred purchase price		259	0	891	1,393
Gain (Loss) on repurchases	[1]	$ 9	$ 0	$ 35	$ 88

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