Segment Information - Revenue From External Customers And Adjusted EBITDA (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Segment information
Revenue from external customers	$ 947	$ 912	$ 2,808	$ 2,730
Communications Segment | Core Network Services
Segment information
Revenue from external customers	759	707	2,232	2,107
Communications Segment | Wholesale Voice Services
Segment information
Revenue from external customers	152	161	467	489
Communications Segment | Other Communications
Segment information
Revenue from external customers	16	27	55	91
Communications Segment
Segment information
Revenue from external customers	927	895	2,754	2,687
Adjusted EBITDA	236	216	687	627
Coal Mining Segment
Segment information
Revenue from external customers	20	17	54	43
Adjusted EBITDA	$ 2	$ 2	$ 2	$ 0