New Accounting Pronouncement and Changes in Accounting or Estimates Narrative (Details) $ in Millions	3 Months Ended
Mar. 31, 2016 USD ($) aircraft
Accounting Changes and Error Corrections [Abstract]
Change In Accounting Estimate Financial Effect On Depreciation Expense for the Remainder of 2016 \| $	$ 88
Additional 737 NG 800 Firm Orders \| aircraft	33

Represents the increase in depreciation expense, excluding the impact of profitsharing and income taxes, resulting from the change in the estimated residual values of the Company's remaining owned 737-300 and 737-500 aircraft.

No definition available.

Name:	luv_ChangeInAccountingEstimateFinancialEffectOnDepreciationExpense
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration