Segment Information (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment information
Revenue from external customers	$ 932	$ 908	$ 1,861	$ 1,818
Communications Segment
Segment information
Revenue from external customers	913	892	1,827	1,792
Adjusted EBITDA	226	209	451	411
Core Network Services
Segment information
Revenue from external customers	744	699	1,473	1,400
Wholesale Voice Services
Segment information
Revenue from external customers	151	163	315	328
Other Communications
Segment information
Revenue from external customers	18	30	39	64
Coal Mining Segment
Segment information
Revenue from external customers	19	16	34	26
Adjusted EBITDA				$ (2)