Sale Of Equipment Installment Receivables (Finance Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes In Other Assets [Line Items]
Cash proceeds received	$ 980	$ 556	$ 3,553	$ 1,375
Deferred purchase price recorded	456	324	1,819	889
Finance Receivables [Member]
Changes In Other Assets [Line Items]
Receivables sold during period	1,601	1,028	5,964	2,665
Finance Receivables Net [Member]
Changes In Other Assets [Line Items]
Receivables sold during period	$ 1,431	$ 885	$ 5,367	$ 2,276