Basis of Presentation and Summary of Significant Accounting Policies-Basis of Presentation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2013	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, 2012 Accumulated amortization	Dec. 31, 2011 Accumulated amortization	Dec. 31, 2012 Software and Software Development Costs	Dec. 31, 2011 Software and Software Development Costs	Dec. 31, 2012 Amortization Expense	Dec. 31, 2011 Amortization Expense	Dec. 31, 2013 Deferred Tax Benefit [Member]	Dec. 31, 2013 Goodwill [Member]	Dec. 31, 2012 Change in Estimates of Economic Lives and Net Salvage Value	Dec. 31, 2012 Minimum Change in Estimates of Capitalized Labor	Dec. 31, 2012 Maximum Change in Estimates of Capitalized Labor	Dec. 31, 2014 Forecast Change in Estimates of Economic Lives and Net Salvage Value
Change in accounting estimates
Labor capitalized as an asset																									$ 40	$ 55
Operating expenses										(16,642)		(15,663)		(13,326)											40	55
Net (loss) income		239	(1,045)	269	298	233	270	74	200	(239)		777		573										16	25	34
Basic earnings per common share (in dollars per share)		$ 0.41	$ (1.76)	$ 0.45	$ 0.48	$ 0.37	$ 0.43	$ 0.12	$ 0.32	$ (0.40)		$ 1.25		$ 1.07										$ 0.03	$ 0.04	$ 0.05
Diluted earnings per common share (in dollars per share)		$ 0.41	$ (1.76)	$ 0.44	$ 0.48	$ 0.37	$ 0.43	$ 0.12	$ 0.32	$ (0.40)	[1]	$ 1.25	[1]	$ 1.07	[1]									$ 0.03	$ 0.04	$ 0.05
Depreciation										2,952		3,070		2,593										26			78
Prior period reclassification adjustment																(30)	(8)	123	83	28	8	105	105
Sale of wireless spectrum assets	43
Gain on sale of wireless spectrum assets	32
Reclassification of wireless spectrum assets				$ 53

[1] For the year ended December 31, 2013, we excluded from the calculation of diluted loss per share 1.3 million shares potentially issuable under incentive compensation plans or convertible securities, as their effect, if included, would have been anti-dilutive.