Equipment Installment Plan Receivables (Receivables) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013 Equipment Installment Plan Receivable [Member]	Dec. 31, 2012 Equipment Installment Plan Receivable [Member]	Dec. 31, 2011 Equipment Installment Plan Receivable [Member]	Dec. 31, 2013 Equipment Installment Plan Receivable [Member] Deferred interest [Member]	Dec. 31, 2012 Equipment Installment Plan Receivable [Member] Deferred interest [Member]	Dec. 31, 2013 Equipment Installment Plan Receivable [Member] Allowances [Member]	Dec. 31, 2012 Equipment Installment Plan Receivable [Member] Allowances [Member]	Dec. 31, 2013 Accounts Receivable, Net [Member] Equipment Installment Plan Receivable [Member]	Dec. 31, 2012 Accounts Receivable, Net [Member] Equipment Installment Plan Receivable [Member]	Dec. 31, 2013 Other Assets [Member] Equipment Installment Plan Receivable [Member]	Dec. 31, 2012 Other Assets [Member] Equipment Installment Plan Receivable [Member]
Receivables [Abstract]
Equipment installment plan, maximum payment term	24 months
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, gross		$ 2,882	$ 816		$ 2,882
Equipment installment plan receivables, allowances		(336)	(125)	(51)	(276)	(110)	(60)	(15)
Equipment installment plan receivables, net of deferred interest		2,606	706
Equipment installment plan receivables		$ 2,546	$ 691						$ 1,471	$ 475	$ 1,075	$ 216