Other Financial Information (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
	Jan. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Other Current Assets
Prepaid expenses		$ 257		$ 240
Materials, supplies and inventory		125		107
Assets held for sale		96
Deferred activation and installation charges current		53		25
Other		21		21
Total other current assets		552		393
Reclassification from other intangible assets, net to current assets other			154
Sale of wireless spectrum assets	43	58
Gain on sale of wireless spectrum assets	32
Accounts payable		1,207		1,400
Other Current Liabilities
Accrued rent		48		44
Legal reserves		39		44
Other		147		167
Total other current liabilities		234		255
Current liabilities
Book overdraft balance		$ 132		$ 61