Accounting changes and new accounting pronouncements (Details) (Change in Spoilage Estimate [Domain], USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2014	Sep. 30, 2014
Change in Spoilage Estimate [Domain]
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate Financial Effect on Passenger Revenue	$ 47
Change in accounting estimate, financial effect on net income		$ 25
Change in accounting estimate,financial effect on earnings per share		$ 0.04

Represents the increase in Passenger revenues, excluding the impact of profit sharing or income taxes, resulting from the change in the spoilage estimate.

No definition available.

Name:	luv_ChangeinAccountingEstimateFinancialEffectonPassengerRevenue
Namespace Prefix:	luv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration