Operating Segments and Related Disclosures

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Operating Segments and Related Disclosures

Operating Segments and Related Disclosures

The Company is managed as a single business unit that provides air transportation for passengers. Operating revenues by geographic region as defined by the Department of Transportation (DOT) area are summarized below:

	2017		2016		2015
	(in millions)
DOT—Domestic	$	2,435.9	$	2,136.2	$	1,940.2
DOT—Latin America	211.8		185.8		201.3
Total	$	2,647.7	$	2,322.0	$	2,141.5

During 2017, 2016 and 2015, no revenue from any one foreign country represented greater than 4% of the Company’s total passenger revenue. The Company attributes operating revenues by geographic region based upon the origin and destination of each passenger flight segment. The Company’s tangible assets consist primarily of flight equipment, which are mobile across geographic markets and, therefore, have not been allocated.