Document and Entity Information Document Information [Table] Class of Stock [Axis] Class of Stock [Domain] Series A common stock Series A common stock Series B common stock Series B common stock Series C common stock Series C common stock Represents information pertaining to Series A cumulative redeemable preferred stock. Series A Cumulative Redeemable Preferred Stock. Series A cumulative redeemable preferred stock Document Information [Line Items] Document Type Document Annual Report Document Period End Date Document Transition Report Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company ICFR Auditor Attestation Flag Document Financial Statement Error Correction [Flag] Entity Shell Company Entity Public Float Entity Common Stock, Shares Outstanding Auditor Name Auditor Firm ID Auditor Location Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Central Index Key Amendment Flag Documents Incorporated by Reference [Text Block] Consolidated Balance Sheets Statement [Table] Statement [Line Items] Statement Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Amount of cash restricted as to withdrawal or usage, and other assets classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Restricted Cash And Other Current Assets Restricted cash and other current assets Disposal Group, Including Discontinued Operation, Assets, Current Current assets of discontinued operations Total current assets Assets, Current Current assets Total current assets Equity Method Investments Investment in Charter, accounted for using the equity method (note 6) Carrying value of equity method investment Amount of cash restricted as to withdrawal or usage, and other assets classified as non current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Restricted Cash And Other Assets, Non Current Restricted cash and other assets, net Other Assets, Noncurrent Other assets, net Other assets Disposal Group, Including Discontinued Operation, Assets, Noncurrent Non-current assets of discontinued operations Assets Total assets Liabilities and Equity [Abstract] Liabilities and Equity Liabilities, Current [Abstract] Current liabilities: Taxes Payable, Current Taxes payable Debt, Current Current portion of debt, including $956 and zero measured at fair value, respectively (note 7) Other Liabilities, Current Other current liabilities Disposal Group, Including Discontinued Operation, Liabilities, Current Current liabilities of discontinued operations Total current liabilities Liabilities, Current Current liabilities Total current liabilities Long-term Debt, Excluding Current Maturities Long-term debt, net, including zero and $1,897 measured at fair value, respectively (note 7) Total long-term debt Deferred Tax Liabilities, Net, Noncurrent Deferred income taxes Deferred income tax liabilities (note 8) Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Noncurrent Preferred stock (note 9) Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent Non-current liabilities of discontinued operations Liabilities Total liabilities Stockholders' Equity Attributable to Parent [Abstract] Equity Common Stock, Value, Issued Common stock Additional Paid in Capital. Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive earnings (loss), net of taxes Retained Earnings (Accumulated Deficit) Retained earnings Stockholders' Equity Attributable to Parent Equity Total stockholders' equity Stockholders' Equity Attributable to Noncontrolling Interest Non-controlling interests Cumulative Effect on Retained Earnings, Net of Tax Balance Balance Total equity Commitments and Contingencies. Commitments and contingencies (note 11) Liabilities and Equity Total liabilities and equity Short-Term Debt, Fair Value Current portion of debt fair value Long-term Debt, Fair Value Long-term debt fair value Common Stock, Par or Stated Value Per Share Common stock par value Common Stock, Shares Authorized Common stock shares authorized Common Stock, Shares, Issued common stock shares issued Common Stock, Shares, Outstanding Common stock shares outstanding Consolidated Statements of Operations Cost and expenses: Operating costs and expenses: Amount of general and administrative expense including stock based compensation incurred during the period. General And Administrative Expense Including Stock Based Compensation General and administrative, including stock-based compensation Operating income (loss) Operating income Operating income (loss) Operating income (loss) Nonoperating Income (Expense) [Abstract] Other income (expense): Interest Expense Interest expense (including amortization of deferred loan fees) Income (Loss) from Equity Method Investments Share of (earnings) losses of affiliate, net Share of earnings (losses) of affiliate (note 6) Share of equity investment income (losses) Gain (Loss) on Sale of Previously Unissued Stock by Subsidiary or Equity Investee, Nonoperating Income (Gain) loss on dilution of investment in affiliate Gain (loss) on dilution of investment in affiliate (note 6) (Loss) on dilution of investment in affiliate Gain (Loss) on Investments Realized and unrealized (gains) losses on financial instruments, net Realized and unrealized gains (losses) on financial instruments, net (note 5) Realized and unrealized gains (losses) on financial instruments Other Nonoperating Income (Expense) Other, net Other income (expense), net Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Earnings (loss) before income taxes Income Tax Expense (Benefit) Income tax benefit (expense) Income tax (expense) benefit Total income tax (benefit) expense Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Net earnings (loss) from continuing operations Net earnings (loss) from continuing operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net earnings (loss) from discontinued operations Net earnings (loss) from discontinued operations Net earnings (loss) Net earnings (loss) Income (Loss) from Continuing Operations, Per Basic Share Basic net earnings (loss) from continuing operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share (note 3) Basic net earnings (loss) from continuing operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Basic net earnings (loss) from discontinued operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share (note 3) Basic net earnings (loss) from discontinued operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share Income (Loss) from Continuing Operations, Per Diluted Share Diluted net earnings (loss) from continuing operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share (note 3) Diluted net earnings (loss) from continuing operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Diluted net earnings (loss) from discontinued operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share (note 3) Diluted net earnings (loss) from discontinued operations attributable to Series A, Series B and Series C Liberty Broadband shareholders per common share Consolidated Statements of Comprehensive Earnings (Loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive earnings (loss), net of taxes: Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax Credit risk on fair value debt instruments gains (loss) Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax Recognition of previously unrealized losses (gains) on debt, net OCI, Equity Method Investment, after Tax Other Amount after tax and reclassification adjustments of other comprehensive income (loss) from continuing operations. Other Comprehensive Income (Loss) from Continuing Operations, Net of Tax Other comprehensive earnings (loss) from continuing operations Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive earnings (loss) attributable to Liberty Broadband shareholders Consolidated Statements of Cash Flows Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Cash flows from operating activities: Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net earnings (loss) Net earnings (loss) Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net earnings (loss) to net cash from operating activities: Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest (Earnings) loss from discontinued operations Net earnings (loss) from discontinued operations Share-based Compensation Stock-based compensation Deferred Income Tax Expense (Benefit) Deferred income tax expense (benefit) Total deferred income tax (benefit) expense Amount of Indemnification paid to GCI Liberty State Indemnification Paid to Gci Liberty State indemnification paid to GCI Liberty Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Operating Assets Current and other assets The increase (decrease) during the reporting period in the aggregate amount of payables and other liabilities that result from activities that generate operating income. Increase Decrease In Payables And Other Liabilities Payables and other liabilities Increase (Decrease) in Accrued Taxes Payable Taxes payable Cash Provided by (Used in) Operating Activity, Continuing Operation Net cash provided by (used in) operating activities Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] Cash flows from investing activities: Proceeds from Sale of Equity Method Investments Amount of Charter sold Cash received for Charter shares repurchased by Charter The cash inflow from the release of escrow related to dispositions. Proceeds From Release Of Escrow From Dispositions Cash released from escrow related to dispositions Payments to Acquire Investments Purchase of investments Payments for (Proceeds from) Other Investing Activities Other investing activities, net Cash Provided by (Used in) Investing Activity, Continuing Operation Net cash provided by (used in) investing activities Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Cash flows from financing activities: Proceeds from Issuance of Long-term Debt Borrowings of debt Repayments of Long-term Debt Repayment of debt Payments for Repurchase of Common Stock Repurchases of Liberty Broadband common stock Repurchase of common stock Payment For Indemnification. Payment For Indemnification Indemnification payment to QVC Group The cash inflow associated with the distributions from former subsidiary. Proceeds from Distributions from Former Subsidiary Distribution from former subsidiary Proceeds from (Payments for) Other Financing Activities Other financing activities, net Cash Provided by (Used in) Financing Activity, Continuing Operation Net cash provided by (used in) financing activities Cash Provided by (Used in) Discontinued Operation [Abstract] Net cash provided by (used in) discontinued operations: Cash Provided by (Used in) Operating Activity, Discontinued Operation Cash provided by (used in) operating activities Cash Provided by (Used in) Investing Activity, Discontinued Operation Cash provided by (used in) investing activities Cash Provided by (Used in) Financing Activity, Discontinued Operation Cash provided by (used in) financing activities Cash Provided by (Used in) Discontinued Operation Net cash provided by (used in) by discontinued operations Cash and Cash Equivalents, Period Increase (Decrease) Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation Cash, cash equivalents, restricted cash and restricted cash equivalents, end of period Cash, cash equivalents, restricted cash and restricted cash equivalents, beginning of period Condensed Consolidated Statements of Equity Equity Components [Axis] Equity Component [Domain] Common stock Common stock Additional paid-in capital Additional paid-in capital Accumulated other comprehensive earnings (loss) Accumulated other comprehensive earnings (loss) Retained earnings Retained earnings (accumulated deficit) Noncontrolling interest in equity of subsidiaries Noncontrolling interest in equity of subsidiaries Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other comprehensive earnings (loss), net of taxes Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Stock-based compensation Stockholders' Equity Note, Spinoff Transaction GCI Divestiture Stock Repurchased During Period, Value Liberty Broadband stock repurchases The increase (decrease) in equity due to noncontrolling interest activity at a subsidiary. Noncontrolling Interest Activity In Subsidiary Noncontrolling interest activity at Charter and other Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Basis of Presentation Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Discontinued Operations Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Supplemental Disclosures to Consolidated Statements of Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Supplemental Disclosures to Consolidated Statements of Cash Flows Assets and Liabilities Measured at Fair Value Fair Value Disclosures [Text Block] Assets and Liabilities Measured at Fair Value Investment in Charter Accounted for Using the Equity Method Equity Method Investments and Joint Ventures Disclosure [Text Block] Investment in Charter Accounted for Using the Equity Method Debt Debt Disclosure [Text Block] Debt Income Taxes Income Tax Disclosure [Text Block] Income Taxes Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Segment Information Segment Reporting Disclosure [Text Block] Segment Information Quarterly Financial Information (unaudited) Quarterly Financial Information [Text Block] Quarterly Financial Information (unaudited) Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents and Restricted Cash and Restricted Cash Equivalents Equity Method Investments Policy Investments in Equity Method Affiliates Investment, Policy [Policy Text Block] Other Investments Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] StockBased Compensation Income Tax, Policy [Policy Text Block] Income Taxes Disclosure of accounting policy for estimating its liability as of the balance sheet date for potential financial exposure. Loss Contingencies Comprehensive Income, Policy [Policy Text Block] Comprehensive Earnings (Loss) Earnings Per Share, Policy [Policy Text Block] Earnings Attributable to Liberty Broadband Stockholders per Common Share