Other Financial Information (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2016	Dec. 31, 2015
Prepaid Expenses and Other Current Assets [Abstract]
Prepaid expenses	$ 285	$ 238
Materials, supplies and inventory	138	144
Assets held for sale	6	8
Deferred activation and installation charges	108	105
Other	91	86
Total other current assets	628	581
Accounts Payable, Current [Abstract]
Accounts payable	1,067	968
Book overdraft balance	46	68
Capital expenditures incurred but not yet paid	119	94
Other Current Liabilities
Accrued rent	30	32
Legal contingencies	36	20
Other	206	168
Total other current liabilities	$ 272	$ 220

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.