Products and Services Revenues (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) category segment	Sep. 30, 2014 USD ($)
Products and Services Revenues
Number of categories of products and services (categories) | category			3
Total operating revenues	$ 2,287	$ 2,198	$ 6,726	$ 6,615
USF surcharges included in operating revenues	37	37	$ 111	114
Number of reportable segments (segments) | segment			1
Strategic services
Products and Services Revenues
Total operating revenues	852	858	$ 2,569	2,574
Legacy services
Products and Services Revenues
Total operating revenues	689	740	2,096	2,264
Affiliates and other services
Products and Services Revenues
Total operating revenues	$ 746	$ 600	$ 2,061	$ 1,777