Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

+ Details

Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended								3 Months Ended							3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Convertible Senior Notes due 2013 (15.0%)	Mar. 31, 2012 Convertible Senior Notes due 2013 (15.0%)	Dec. 31, 2011 Convertible Senior Notes due 2013 (15.0%)	Sep. 30, 2011 Convertible Senior Notes due 2013 (15.0%)	Mar. 31, 2013 Venezuela official fixed exchange rate (VEF)	Feb. 13, 2013 Venezuela official fixed exchange rate (VEF)	Dec. 31, 2012 Venezuela official fixed exchange rate (VEF)	Dec. 31, 2012 Level 3 Communications, Inc.	Dec. 31, 2011 Level 3 Communications, Inc.	Dec. 31, 2010 Level 3 Communications, Inc.	Dec. 31, 2009 Level 3 Communications, Inc.	Mar. 31, 2013 Level 3 Communications, Inc. Convertible Senior Notes due 2013 (15.0%)	Jan. 15, 2013 Level 3 Communications, Inc. Convertible Senior Notes due 2013 (15.0%)	Dec. 31, 2012 Level 3 Communications, Inc. Convertible Senior Notes due 2013 (15.0%)	Mar. 31, 2012 Level 3 Communications, Inc. Convertible Senior Notes due 2013 (15.0%)
Subsequent Events
Extinguishment of Debt, Amount																$ 172
Debt instrument, stated interest rate (as a percent)					15.00%	15.00%	15.00%	15.00%									15.00%	15.00%	15.00%
Foreign currency exchange rate, translation										6.30	4.30
Cash and cash equivalents	979	918	616	836							(22)	253	2	173	236
Net monetary assets subject to foreign currency restrictions											(20)
Other, net	$ (58)	$ (23)	$ 20						$ (20)