SUBSEQUENT EVENTS (Details)	1 Months Ended	3 Months Ended	60 Months Ended	120 Months Ended
	Apr. 28, 2020 USD ($)	Jun. 30, 2020	Apr. 19, 2030	Apr. 19, 2030	Apr. 24, 2020 USD ($)	Apr. 21, 2020 USD ($) shares	Apr. 20, 2020 USD ($) BasisPoints shares	Apr. 09, 2020 $ / shares	Apr. 01, 2020 USD ($)	Mar. 31, 2020
Subsequent Event [Line Items]
Entity Number of Employees										60,000
Subsequent Event
Subsequent Event [Line Items]
Total Expected Receipts of Relief Through Payroll Support Program of CARES Act							$ 3,300,000,000
Expected Unsecured Term Loan Through Payroll Support Program of CARES Act							948,000,000
Proceeds from Payroll Support Program Grant						$ 1,600,000,000
Percent of Total Expected Proceeds Received from Payroll Support Program Grant						50.00%
Unsecured Term Loan Through Payroll Support Program of CARES Act						$ 459,000,000
Principal Amount Increase on Unsecured Term Loan Through Payroll Support Program of CARES Act				30.00%
Principal Amount Increase on Warrants Issued to Treasury Through Payroll Support Program of CARES Act				10.00%
Percent of Total Expected Proceeds Received in 2Q20 from Payroll Support Program of CARES Act		90.00%
Expected Eligibility Amount for Secured Loans Through CARES Act							$ 2,800,000,000
Expected Interest Rate for Secured Loans Through CARES Act | BasisPoints							250
Expected Warrant Issuance to Treasury for Secured Loans Through CARES Act | shares							7,600,000
LUV Common Stock Warrants | Subsequent Event
Subsequent Event [Line Items]
Class of Warrant or Right, Outstanding | shares						1,300,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares							2,600,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								$ 36.47
Amended 364-Day Term Loan Credit Facility | Subsequent Event
Subsequent Event [Line Items]
364-Day Term Loan Credit Facility	$ 3,680,000,000								$ 2,300,000,000
Unsecured Debt | CARES Act Unsecured Loan | Subsequent Event
Subsequent Event [Line Items]
Stated interest rate						1.00%
Accordian Feature to Amended 364-Day Term Loan Credit Facility [Member] | Amended 364-Day Term Loan Credit Facility | Subsequent Event
Subsequent Event [Line Items]
364-Day Term Loan Credit Facility					$ 350,000,000
Accordian Feature on Short-term Debt					$ 417,000,000
Total Funds Available Amended 364-Day Term Loan Credit Facility	$ 3,750,000,000
Forecast | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Unsecured Debt | CARES Act Unsecured Loan | Subsequent Event
Subsequent Event [Line Items]
Basis spread on variable rate (percent) April 21, 2025 and beyond			2.00%