Business Combinations (Transaction with MetroPCS - Preliminary Purchase Price Allocation) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 MetroPCS [Member]	Dec. 31, 2012 MetroPCS [Member]	Apr. 30, 2013 MetroPCS [Member]
Business Acquisition [Line Items]
Cash and cash equivalents														$ 2,144
Accounts receivable, net														98
Inventory														171
Other current assets														240
Property and equipment														1,475
Spectrum licenses														3,818
Other intangible assets														1,376
Other assets														10
Total assets acquired														9,332
Accounts payable and accrued liabilities														475
Deferred revenues														187
Other current liabilities														15
Deferred tax liabilities														735
Long-term debt														6,277
Other long-term liabilities														355
Total liabilities assumed														8,044
Net identifiable assets acquired														1,288
Goodwill	1,683				0				1,683	0	8,134			1,683
Net assets acquired														2,971
Goodwill deductible for income tax purposes	0								0
MetroPCS transaction related costs												41	7
MetroPCS integration related costs	$ 57	$ 12	$ 26	$ 13	$ 7	$ 0	$ 0	$ 0	$ 108	$ 7	$ 0	$ 67