Segment Information Revenue From External Customers (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment information
Revenue from external customers	$ 1,602	$ 1,569	$ 1,565	$ 1,577	$ 1,614	$ 1,590	$ 1,586	$ 1,586	$ 6,313	$ 6,376	$ 4,333
Core Network Service [Member]
Segment information
Revenue from external customers									5,591	5,463	3,566
Core Network Service [Member] | North America
Segment information
Revenue from external customers									3,949	3,840	2,915
Core Network Service [Member] | Europe
Segment information
Revenue from external customers									888	911	475
Core Network Service [Member] | Latin America
Segment information
Revenue from external customers									754	712	176
Wholesale Voice Services and Other [Member]
Segment information
Revenue from external customers									722	913	767
Wholesale Voice Services and Other [Member] | North America
Segment information
Revenue from external customers									681	863	731
Wholesale Voice Services and Other [Member] | Europe
Segment information
Revenue from external customers									31	40	34
Wholesale Voice Services and Other [Member] | Latin America
Segment information
Revenue from external customers									$ 10	$ 10	$ 2