Annual report pursuant to Section 13 and 15(d) Cover Financial Statements Notes to Financial Statements Accounting Policies Notes Tables Notes Details Document and Entity Information Document and Entity Information - USD ($) $ in Billions 12 Months Ended Dec. 31, 2019 Jan. 31, 2020 Jun. 28, 2019 Document Information [Line Items] Document Type 10-K Document Annual Report true Document Period End Date Dec. 31, 2019 Document Transition Report false Entity File Number 001-36713 Entity Registrant Name LIBERTY BROADBAND CORPORATION Entity Incorporation, State or Country Code DE Entity Tax Identification Number 47-1211994 Entity Address, Address Line One 12300 Liberty Boulevard Entity Address, City or Town Englewood Entity Address, State or Province CO Entity Address, Postal Zip Code 80112 City Area Code 720 Local Phone Number 875-5700 Entity Well-known Seasoned Issuer Yes Entity Voluntary Filers No Entity Current Reporting Status Yes Entity Interactive Data Current Yes Entity Filer Category Large Accelerated Filer Entity Small Business false Entity Emerging Growth Company false Entity Shell Company false Entity Public Float $ 18.0 Current Fiscal Year End Date --12-31 Document Fiscal Year Focus 2019 Document Fiscal Period Focus FY Entity Central Index Key 0001611983 Amendment Flag false Series A common stock Document Information [Line Items] Title of 12(b) Security Series A common stock Trading Symbol LBRDA Security Exchange Name NASDAQ Entity Common Stock, Shares Outstanding 26,493,289 Series B common stock Document Information [Line Items] Entity Common Stock, Shares Outstanding 2,451,828 Series C common stock Document Information [Line Items] Title of 12(b) Security Series C common stock Trading Symbol LBRDK Security Exchange Name NASDAQ Entity Common Stock, Shares Outstanding 152,957,753