Operating segment information is as follows (in millions):



	Three Months Ended June 30, 2017
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger
Mainline	$	1,556		$	—	$	—		$	—		$	1,556		$	—		$	1,556
Regional	—			251		—			—			251			—			251
Total passenger revenues	1,556			251		—			—			1,807			—			1,807
CPA revenues	—			—		108			(108		)	—			—			—
Freight and mail	31			1		—			—			32			—			32
Other—net	244			19		1			(1		)	263			—			263
Total operating revenues	1,831			271		109			(109		)	2,102			—			2,102
Operating expenses
Operating expenses, excluding fuel	1,026			206		116			(107		)	1,241			24			1,265
Economic fuel	304			39		—			(1		)	342			2			344
Total operating expenses	1,330			245		116			(108		)	1,583			26			1,609
Nonoperating income (expense)
Interest income	9			—		—			—			9			—			9
Interest expense	(23		)	—		(3		)	—			(26		)	—			(26		)
Other	3			—		1			(1		)	3			—			3
Total Nonoperating income (expense)	(11		)	—		(2		)	(1		)	(14		)	—			(14		)
Income (loss) before income tax	$	490		$	26	$	(9	)	$	(2	)	$	505		$	(26	)	$	479



	Three Months Ended June 30, 2016
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger
Mainline	$	1,036		$	—	$	—		$	—		$	1,036		$	—		$	1,036
Regional	—			227		—			—			227			—			227
Total passenger revenues	1,036			227		—			—			1,263			—			1,263
CPA revenues	—			—		110			(110		)	—			—			—
Freight and mail	26			1		—			—			27			—			27
Other—net	184			19		1			—			204			—			204
Total operating revenues	1,246			247		111			(110		)	1,494			—			1,494
Operating expenses
Operating expenses, excluding fuel	679			192		101			(111		)	861			14			875
Economic fuel	180			31		—			—			211			(10		)	201
Total operating expenses	859			223		101			(111		)	1,072			4			1,076
Nonoperating income (expense)
Interest income	6			—		1			—			7			—			7
Interest expense	(4		)	—		(4		)	(1		)	(9		)	—			(9		)
Other	3			—		—			1			4			—			4
Total Nonoperating income (expense)	5			—		(3		)	—			2			—			2
Income (loss) before income tax	$	392		$	24	$	7		$	1		$	424		$	(4	)	$	420



	Six Months Ended June 30, 2017
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger
Mainline	$	2,828		$	—	$	—		$	—		$	2,828		$	—		$	2,828
Regional	—			463		—			—			463			—			463
Total passenger revenues	2,828			463		—			—			3,291			—			3,291
CPA revenues	—			—		205			(205		)	—			—			—
Freight and mail	54			2		—			—			56			—			56
Other—net	466			36		2			—			504			—			504
Total operating revenues	3,348			501		207			(205		)	3,851			—			3,851
Operating expenses
Operating expenses, excluding fuel	2,024			406		219			(204		)	2,445			64			2,509
Economic fuel	596			75		—			—			671			12			683
Total operating expenses	2,620			481		219			(204		)	3,116			76			3,192
Nonoperating income (expense)
Interest income	16			—		—			—			16			—			16
Interest expense	(45		)	—		(5		)	(1		)	(51		)	—			(51		)
Other	6			—		1			—			7			—			7
Total Nonoperating income (expense)	(23		)	—		(4		)	(1		)	(28		)	—			(28		)
Income (loss) before income tax	705			20		(16		)	(2		)	707			(76		)	631



	Six Months Ended June 30, 2016
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger
Mainline	$	1,963		$	—	$	—		$	—		$	1,963		$	—		$	1,963
Regional	—			433		—			—			433			—			433
Total passenger revenues	1,963			433		—			—			2,396			—			2,396
CPA revenues	—			—		213			(213		)	—			—			—
Freight and mail	49			2		—			—			51			—			51
Other—net	356			36		2			—			394			—			394
Total operating revenues	2,368			471		215			(213		)	2,841			—			2,841
Operating expenses
Operating expenses, excluding fuel	1,380			378		206			(213		)	1,751			14			1,765
Economic fuel	324			56		—			—			380			(12		)	368
Total operating expenses	1,704			434		206			(213		)	2,131			2			2,133
Nonoperating income (expense)
Interest income	12			—		1			—			13			—			13
Interest expense	(16		)	—		(5		)	(1		)	(22		)	—			(22		)
Other	10			—		—			3			13			—			13
Total Nonoperating income (expense)	6			—		(4		)	2			4			—			4
Income (loss) before income tax	670			37		5			2			714			(2		)	712


(a)	Includes consolidating entries, Parent Company and other immaterial business units.


(b)	The Air Group Adjusted column represents the financial information that is reviewed by management to assess performance of operations and determine capital allocations and does not include certain income and charges.


(c)	Includes merger-related costs and mark-to-market fuel-hedge accounting charges.

Total assets were as follows (in millions):