Other Financial Information Other Financial Information (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Nov. 03, 2014	Jan. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Prepaid Expenses and Other Current Assets [Abstract]
Prepaid expenses			$ 238	$ 260
Materials, supplies and inventory			144	132
Assets held for sale			8	14
Deferred activation and installation charges			105	103
Other			86	71
Other Assets, Current			581	580
Assets Held-for-sale, Not Part of Disposal Group, Current [Abstract]
Impairment wireless spectrum licenses				14
Proceeds from sale of wireless spectrum	$ 39
Wireless spectrum licenses		$ 43
Gain sale of wireless spectrum		$ 32	0	0	$ 32
Accounts Payable, Current [Abstract]
Accounts payable			968	1,226
Capital expenditures included in accounts payable			94	185
Book overdraft balance			68	80
Other current liabilities:
Accrued rent			32	34
Legal reserves			20	27
Other			168	149
Total other current liabilities			$ 220	$ 210