Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Components of Deferred Tax Assets and Liabilities

The components of deferred tax assets and liabilities at December 31, 2015 and 2014, are as follows:

(in millions)	2015		2014
DEFERRED TAX LIABILITIES:
Accelerated depreciation	$	4,429	$	4,277
Other	62		51
Total deferred tax liabilities	4,491		4,328
DEFERRED TAX ASSETS:
Fuel derivative instruments	750		521
Capital and operating leases	81		125
Construction obligation	289		209
Accrued engine maintenance	74		83
Accrued employee benefits	541		334
State taxes	62		65
Business partner income	107		90
Other	97		119
Total deferred tax assets	2,001		1,546
Net deferred tax liability	$	2,490	$	2,782

Components of the Income Tax Provision

The provision for income taxes is composed of the following:

(in millions)	2015			2014		2013
CURRENT:
Federal	$	1,292		$	203	$	355
State	114			29		44
Total current	1,406			232		399
DEFERRED:
Federal	(97		)	421		62
State	(11		)	27		(6		)
Total deferred	(108		)	448		56
	$	1,298		$	680	$	455

Income Tax Provision Reconciliation To Federal Income Tax Statutory Rate

The effective tax rate on income before income taxes differed from the federal income tax statutory rate for the following reasons:

(in millions)	2015			2014			2013
Tax at statutory U.S. tax rates	$	1,218		$	636		$	423
Nondeductible items	15			9			10
State income taxes, net of federal benefit	66			37			25
Other, net	(1		)	(2		)	(3		)
Total income tax provision	$	1,298		$	680		$	455