Income Taxes (Tables)

The following table is an analysis of the effective tax rate:



	Years Ended December 31,
(Dollars in millions)	2015		2014 ⁽¹⁾		2013 ⁽¹⁾
Federal income tax rate	35	%	35	%	35	%
Net tax effects of:
State income taxes, net of federal income tax benefit	5		6		5
Tax-exempt interest income	(2	)	(1	)	(1	)
Amortization of LIHC investments	12		6		9
Tax credits	(27	)	(14	)	(15	)
Other	(1	)	(1	)	(2	)
Effective tax rate	22	%	31	%	31	%


(1)	Prior period amounts have been revised to reflect the January 1, 2015 adoption of Accounting Standards Update 2014-01 related to investments in qualified affordable housing projects.

The components of income tax expense were as follows:

The components of the Company's net deferred tax balances as of December 31, 2015 and 2014 were as follows:



	December 31,
(Dollars in millions)	2015		2014 ⁽¹⁾
Deferred tax assets:
Allowance for credit losses	$	392	$	283
Accrued expense, net	274		272
Unrealized losses on pension and postretirement benefits	401		389
Unrealized net losses on securities available for sale	101		97
Fair value adjustments for valuation of FDIC covered assets	125		159
Other	82		63
Total deferred tax assets	1,375		1,263
Deferred tax liabilities:
Leasing	779		759
Intangible assets	98		99
Pension liabilities	427		389
Other	—		5
Total deferred tax liabilities	1,304		1,252
Net deferred tax asset	$	71	$	11

The changes in unrecognized tax positions were as follows:



	Years Ended December 31,
(Dollars in millions)	2015			2014			2013
Balance, beginning of year	$	8		$	16		$	269
Gross increases as a result of tax positions taken during prior periods	1			—			1
Gross decreases as a result of tax positions taken during prior periods	(4		)	(10		)	(256		)
Gross increases as a result of tax positions taken during current period	2			2			2
Balance, end of year	$	7		$	8		$	16