Document and Entity Information	9 Months Ended
Sep. 30, 2011	Nov. 04, 2011 Common Class A	Nov. 04, 2011 Common Class B
Entity Registrant Name	SWIFT TRANSPORTATION Co
Entity Central Index Key	0001492691
Document Type	10-Q
Document Period End Date	Sep. 30, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		79,381,863	60,116,713

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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