Employee Benefit Benefits and Stock-Based Compensation - Outperform Stock Options (Details) (Outperform Stock Options, USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award
Unamortized compensation expense	$ 21
Weighted average period over which unamortized compensation cost will be recognized (in years)	2 years 1 month 28 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Expected Dividend Yield Rate	2.05%	1.83%	2.00%
Expected Life (in years)	3 years	3 years	3 years
Expected Correlation Factor	0.32	0.39	0.40
Theoretical Value	110.00%	120.00%	132.00%
Estimated Forfeiture Rate	20.00%	20.00%	20.00%
Fair value of OSO units awarded	29	12	10
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Options outstanding, beginning (in shares)	1,288,712	1,056,392	1,056,627
Options granted (in shares)	1,195,452	498,618	511,082
Options forfeited (in shares)	(72,335)	(96,174)	(117,362)
Options expired (in shares)	(278,111)	(140,655)	(393,955)
Options exercised (in shares)	(67,299)	(29,469)	0
Options outstanding, ending (in shares)	2,066,419	1,288,712	1,056,392	1,056,627
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Options, Beginning, Initial Strike Price Per Unit, Minimum (in dollars per share)	$ 10.50	$ 10.50	$ 10.50
Options, Beginning, Initial Strike Price Per Unit, Maximum (in dollars per share)	$ 36.60	$ 51.60	$ 91.50
Options, Beginning, Weighted Average Initial Strike Price (in dollars per share)	$ 20.51	$ 22.05	$ 44.25
Options, Beginning, Aggregate Intrinsic Value	$ 1.8	$ 0	$ 5.2		$ 6.6
Options, Beginning, Average Remaining Contractual Term (in years)	1 year 8 months 23 days	1 year 6 months 11 days	1 year 8 months 23 days	1 year 6 months 18 days
Options granted, Initial Strike Price Per Unit, Minimum (in dollars per share)	$ 16.99	$ 14.70	$ 14.10
Options granted, Initial Strike Price Per Unit, Maximum (in dollars per share)	$ 27.53	$ 36.60	$ 24.30
Options granted, Weighted Average Initial Strike Price (in dollars per share)	$ 24.65	$ 23.96	$ 19.50
Options forfeited, Initial Strike Price Per Unit, Minimum (in dollars per share)	$ 12	$ 10.50	$ 10.50
Options forfeited, Initial Strike Price Per Unit, Maximum (in dollars per share)	$ 36.60	$ 51.60	$ 91.50
Options forfeited, Weighted Average Initial Strike Price (in dollars per share)	$ 21.80	$ 22.36	$ 25.80
Options expired, Initial Strke Price Per Unit, Minimum (in dollars per share)	$ 15	$ 31.80	$ 45.45
Options expired, Initial Strke Price Per Unit, Maximum (in dollars per share)	$ 22.65	$ 51.60	$ 91.50
Options expired, Weighted Average Initial Strike Price (in dollars per share)	$ 18.45	$ 44.64	$ 76.95
Options exercised, Initial Strike Price Per Unit, Minimum (in dollars per share)	$ 10.50	$ 14.10	$ 0
Options exercised, Initial Strike Price Per Unit, Maximum (in dollars per share)	$ 13.80	$ 15.75	$ 0
Options exercised, Weighted Average Initial Strike Price (in dollars per share)	$ 12.48	$ 14.93	$ 0.00
Options, Ending, Initial Strike Price Per Unit, Minimum (in dollars per share)	$ 14.10	$ 10.50	$ 10.50	$ 10.50
Options, Ending, Initial Strike Price Per Unit, Maximum (in dollars per share)	$ 36.60	$ 36.60	$ 51.60	$ 91.50
Options, Ending, Weighted Average Initial Strike Price (in dollars per share)	$ 23.40	$ 20.51	$ 22.05	$ 44.25
Options, Ending, Average Remaining Contractual Term (in years)	1 year 8 months 23 days	1 year 6 months 11 days	1 year 8 months 23 days	1 year 6 months 18 days
Prior to March 31, 2007
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Life of Award	3 years
On or After April 1, 2007
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Life of Award	3 years
Percent vested after three years	100.00%
S and P 500 Index
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Expected volatility rate	23.00%	30.00%	30.00%
Level 3 Communications, Inc.
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Expected volatility rate	39.00%	44.00%	51.00%
Performance Range 1
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Performance Qualifier to Index, Maximum	0.00%				0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Success Multiplier of Pre Multiplier Gain	0.00				0.00
Performance Range 2
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Performance Qualifier to Index, Minimum	0.00%				0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Performance Qualifier to Index, Maximum	11.00%				11.00%
Share-based Compensation Arrangement by Share-based Payment Award, Success Multiplier of Pre Multiplier Gain	0.36				0.36
Performance Range 3
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Performance Qualifier to Index, Minimum	11.00%				11.00%
Share-based Compensation Arrangement by Share-based Payment Award, Success Multiplier of Pre Multiplier Gain	4.00				4.00