Change In Accounting Estimate (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2015
Change in Accounting Estimate [Abstract]
Change in Accounting Estimate Financial Effect on Passenger Revenue, Spoilage Estimate	$ 30	$ 115
Change in accounting estimate, financial effect on net income, spoilage adjustment	$ 16	$ 61
Change in accounting estimate,financial effect on earnings per share	$ 0.02	$ 0.09

Represents the increase in net income, including the impact of profit sharing and income taxes, resulting from the change in the spoilage estimate.

No definition available.

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