Operating segment information is as follows (in millions):



	Three Months Ended June 30, 2018
	Mainline			Regional			Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	1,711		$	286		$	—		$	—		$	1,997		$	—		$	1,997
CPA revenues	—			—			137			(137		)	—			—			—
Mileage plan other revenue	99			9			—			—			108			—			108
Cargo and other	49			1			1			—			51			—			51
Total operating revenues	1,859			296			138			(137		)	2,156			—			2,156
Operating expenses
Operating expenses, excluding fuel	1,135			249			123			(136		)	1,371			39			1,410
Economic fuel	432			65			—			—			497			(22		)	475
Total operating expenses	1,567			314			123			(136		)	1,868			17			1,885
Nonoperating income (expense)
Interest income	13			—			—			(3		)	10			—			10
Interest expense	(22		)	—			(5		)	2			(25		)	—			(25		)
Interest capitalized	4			—			—			—			4			—			4
Other—net	1			(2		)	—			—			(1		)	—			(1		)
Total Nonoperating income (expense)	(4		)	(2		)	(5		)	(1		)	(12		)	—			(12		)
Income (loss) before income tax	$	288		$	(20	)	$	10		$	(2	)	$	276		$	(17	)	$	259



	Three Months Ended June 30, 2017^(d)
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	1,677		$	268	$	—		$	—		$	1,945		$	—		$	1,945
CPA revenues	—			—		108			(108		)	—			—			—
Mileage plan other revenue	101			8		—			—			109			—			109
Cargo and other	45			2		1			—			48			—			48
Total operating revenues	1,823			278		109			(108		)	2,102			—			2,102
Operating expenses
Operating expenses, excluding fuel	1,030			206		116			(105		)	1,247			24			1,271
Economic fuel	304			38		—			—			342			2			344
Total operating expenses	1,334			244		116			(105		)	1,589			26			1,615
Nonoperating income (expense)
Interest income	10			—		—			(1		)	9			—			9
Interest expense	(24		)	—		(3		)	1			(26		)	—			(26		)
Interest capitalized	3			—		1			—			4			—			4
Other—net	—			—		—			—			—			—			—
Total Nonoperating income (expense)	(11		)	—		(2		)	—			(13		)	—			(13		)
Income (loss) before income tax	$	478		$	34	$	(9	)	$	(3	)	$	500		$	(26	)	$	474



	Six Months Ended June 30, 2018
(in millions)	Mainline			Regional			Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	3,153		$	529		$	—		$	—		$	3,682		$	—		$	3,682
CPA revenues	—			—			247			(247		)	—			—			—
Mileage plan other revenue	197			18			—			—			215			—			215
Cargo and other	88			1			2			—			91			—			91
Total operating revenues	3,438			548			249			(247		)	3,988			—			3,988
Operating expenses
Operating expenses, excluding fuel	2,266			488			227			(247		)	2,734			70			2,804
Economic fuel	799			120			—			—			919			(35		)	884
Total operating expenses	3,065			608			227			(247		)	3,653			35			3,688
Nonoperating income (expense)
Interest income	24			—			—			(6		)	18			—			18
Interest expense	(44		)	—			(10		)	5			(49		)	—			(49		)
Interest capitalized	8			—			1			—			9			—			9
Other	(4		)	(9		)	—			—			(13		)	—			(13		)
Total Nonoperating income (expense)	(16		)	(9		)	(9		)	(1		)	(35		)	—			(35		)
Income (loss) before income tax	$	357		$	(69	)	$	13		$	(1	)	$	300		$	(35	)	$	265



	Six Months Ended June 30, 2017^(d)
(in millions)	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	3,052		$	495	$	—		$	—		$	3,547		$	—		$	3,547
CPA revenues	—			—		205			(205		)	—			—			—
Mileage plan other revenue	194			15		—			—			209			—			209
Cargo and other	81			3		2			—			86			—			86
Total operating revenues	3,327			513		207			(205		)	3,842			—			3,842
Operating expenses
Operating expenses, excluding fuel	2,030			406		219			(203		)	2,452			63			2,515
Economic fuel	596			75		—			—			671			12			683
Total operating expenses	2,626			481		219			(203		)	3,123			75			3,198
Nonoperating income (expense)
Interest income	17			—		—			(1		)	16			—			16
Interest expense	(47		)	—		(5		)	1			(51		)	—			(51		)
Interest capitalized	7			—		1			—			8			—			8
Other	(1		)	—		—			—			(1		)	—			(1		)
Total Nonoperating income (expense)	(24		)	—		(4		)	—			(28		)	—			(28		)
Income (loss) before income tax	$	677		$	32	$	(16	)	$	(2	)	$	691		$	(75	)	$	616


(a)	Includes consolidating entries, Parent Company, McGee Air Services, 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, mark-to-market fuel-hedge accounting charges, and other special items.


(d)	Certain historical information has been adjusted to reflect the adoption of new accounting standards.

Total assets were as follows (in millions):