Operating segment information is as follows (in millions):



	Three Months Ended September 30, 2018
	Mainline			Regional			Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	1,727		$	316		$	—		$	—		$	2,043		$	—		$	2,043
CPA revenues	—			—			128			(128		)	—			—			—
Mileage Plan other revenue	104			10			—			—			114			—			114
Cargo and other	53			—			2			—			55			—			55
Total operating revenues	1,884			326			130			(128		)	2,212			—			2,212
Operating expenses
Operating expenses, excluding fuel	1,126			267			118			(131		)	1,380			22			1,402
Economic fuel	438			70			—			—			508			5			513
Total operating expenses	1,564			337			118			(131		)	1,888			27			1,915
Nonoperating income (expense)
Interest income	15			—			—			(4		)	11			—			11
Interest expense	(20		)	—			(6		)	4			(22		)	—			(22		)
Interest capitalized	4			—			1			—			5			—			5
Other—net	(5		)	(2		)	—			—			(7		)	—			(7		)
Total Nonoperating income (expense)	(6		)	(2		)	(5		)	—			(13		)	—			(13		)
Income (loss) before income tax	$	314		$	(13	)	$	7		$	3		$	311		$	(27	)	$	284



	Three Months Ended September 30, 2017^(d)
	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	1,677		$	281	$	—		$	—		$	1,958		$	—		$	1,958
CPA revenues	—			—		112			(112		)	—			—			—
Mileage Plan other revenue	97			8		—			—			105			—			105
Cargo and other	46			—		1			—			47			—			47
Total operating revenues	1,820			289		113			(112		)	2,110			—			2,110
Operating expenses
Operating expenses, excluding fuel	1,081			219		104			(112		)	1,292			23			1,315
Economic fuel	328			45		—			—			373			(5		)	368
Total operating expenses	1,409			264		104			(112		)	1,665			18			1,683
Nonoperating income (expense)
Interest income	12			—		—			(3		)	9			—			9
Interest expense	(25		)	—		(4		)	3			(26		)	—			(26		)
Interest capitalized	5			—		—			—			5			—			5
Other—net	2			—		—			—			2			—			2
Total Nonoperating income (expense)	(6		)	—		(4		)	—			(10		)	—			(10		)
Income (loss) before income tax	$	405		$	25	$	5		$	—		$	435		$	(18	)	$	417



	Nine Months Ended September 30, 2018
(in millions)	Mainline			Regional			Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	4,880		$	845		$	—		$	—		$	5,725		$	—		$	5,725
CPA revenues	—			—			375			(375		)	—			—			—
Mileage Plan other revenue	301			28			—			—			329			—			329
Cargo and other	141			1			4			—			146			—			146
Total operating revenues	5,322			874			379			(375		)	6,200			—			6,200
Operating expenses
Operating expenses, excluding fuel	3,392			755			345			(378		)	4,114			92			4,206
Economic fuel	1,237			190			—			—			1,427			(30		)	1,397
Total operating expenses	4,629			945			345			(378		)	5,541			62			5,603
Nonoperating income (expense)
Interest income	39			—			—			(10		)	29			—			29
Interest expense	(64		)	—			(16		)	9			(71		)	—			(71		)
Interest capitalized	12			—			2			—			14			—			14
Other	(9		)	(11		)	—			—			(20		)	—			(20		)
Total Nonoperating income (expense)	(22		)	(11		)	(14		)	(1		)	(48		)	—			(48		)
Income (loss) before income tax	$	671		$	(82	)	$	20		$	2		$	611		$	(62	)	$	549



	Nine Months Ended September 30, 2017^(d)
(in millions)	Mainline			Regional		Horizon			Consolidating & Other^(a)			Air Group Adjusted^(b)			Special Items^(c)			Consolidated
Operating revenues
Passenger revenues	$	4,729		$	776	$	—		$	—		$	5,505		$	—		$	5,505
CPA revenues	—			—		317			(317		)	—			—			—
Mileage Plan other revenue	291			23		—			—			314			—			314
Cargo and other	127			3		3			—			133			—			133
Total operating revenues	5,147			802		320			(317		)	5,952			—			5,952
Operating expenses
Operating expenses, excluding fuel	3,111			625		323			(315		)	3,744			86			3,830
Economic fuel	924			120		—			—			1,044			7			1,051
Total operating expenses	4,035			745		323			(315		)	4,788			93			4,881
Nonoperating income (expense)
Interest income	29			—		—			(4		)	25			—			25
Interest expense	(72		)	—		(9		)	4			(77		)	—			(77		)
Interest capitalized	12			—		1			—			13			—			13
Other	1			—		—			—			1			—			1
Total Nonoperating income (expense)	(30		)	—		(8		)	—			(38		)	—			(38		)
Income (loss) before income tax	$	1,082		$	57	$	(11	)	$	(2	)	$	1,126		$	(93	)	$	1,033


(a)	Includes consolidating entries, Air Group 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):