The Company’s

held-to-maturity

investment securities are carried at historical cost, adjusted for amortization of premiums and accretion of discounts and credit-related other-than-temporary impairment. The Company’s

available-for-sale

investment securities are carried at fair value with unrealized net gains or losses reported within accumulated other comprehensive income (loss) in shareholders’ equity.

The amortized cost, other-than-temporary impairment recorded in other comprehensive income (loss), gross unrealized holding gains and losses, and fair value of

held-to-maturity

and

available-for-sale

investment securities were as follows:


	September 30, 2019											December 31, 2018
					Unrealized Losses											Unrealized Losses
(Dollars in Millions)	Amortized Cost		Unrealized Gains		Other-than- Temporary (a)		Other (b)			Fair Value		Amortized Cost		Unrealized Gains		Other-than- Temporary (a)		Other (b)			Fair Value
Held-to-maturity
U.S. Treasury and agencies	$	4,402	$	35	$	—	$	(7)		$	4,430	$	5,102	$	2	$	—	$	(143 )		$	4,961
Residential agency mortgage-backed securities		42,054		289		—		(162	)		42,181		40,920		45		—		(994	)		39,971
Asset-backed securities
Collateralized debt obligations/Collateralized loan obligations		—		1		—		—			1		—		1		—		—			1
Other		5		1		—		—			6		5		2		—		—			7
Obligations of state and political subdivisions		4		—		—		—			4		6		1		—		—			7
Obligations of foreign governments		8		—		—		—			8		9		—		—		—			9
Other		8		—		—		—			8		8		—		—		—			8
Total held-to-maturity	$	46,481	$	326	$	—	$	(169)		$	46,638	$	46,050	$	51	$	—	$	(1,137 )		$	44,964
Available-for-sale
U.S. Treasury and agencies	$	15,543	$	57	$	—	$	(47)		$	15,553	$	19,604	$	11	$	—	$	(358 )		$	19,257
Mortgage-backed securities
Residential agency		50,817		328		—		(202	)		50,943		40,542		120		—		(910	)		39,752
Commercial agency		989		—		—		(5	)		984		2		—		—		—			2
Other asset-backed securities		377		5		—		—			382		397		6		—		—			403
Obligations of state and political subdivisions		6,395		342		—		(2	)		6,735		6,836		37		—		(172	)		6,701
Obligations of foreign governments		1		—		—		—			1		—		—		—		—			—
Total available-for-sale	$	74,122	$	732	$	—	$	(256	)	$	74,598	$	67,381	$	174	$	—	$	(1,440	)	$	66,115

(a)	Represents impairment not related to credit for those investment securities that have been determined to be other-than-temporarily impaired.

(b)	Represents unrealized losses on investment securities that have not been determined to be other-than-temporarily impaired.

The weighted-average maturity of the

available-for-sale

investment securities was 4.0 years at September 30, 2019, compared with 5.4 years at December 31, 2018. The corresponding weighted-average yields were 2.56 percent and 2.57 percent, respectively. The weighted-average maturity of the

held-to-maturity

investment securities was 3.8 years at September 30, 2019, compared with 5.2 years at December 31, 2018. The corresponding weighted-average yields were 2.42 percent and 2.46 percent, respectively.

For amortized cost, fair value and yield by maturity date of

held-to-maturity

and

available-for-sale

investment securities outstanding at September 30, 2019, refer to Table 4 included in Management’s Discussion and Analysis, which is incorporated by reference into these Notes to Consolidated Financial Statements.

Investment securities with a fair value of $11.0 billion at September 30, 2019, and $10.9 billion at December 31, 2018, were pledged to secure public, private and trust deposits, repurchase agreements and for other purposes required by contractual obligation or law. Included in these amounts were securities where the Company and certain counterparties have agreements granting the counterparties the right to sell or pledge the securities. Investment securities securing these types of arrangements had a fair value of $272 million at September 30, 2019, and $2.1 billion at December 31, 2018.

The following table provides inf

rmation about the amount of interest income from taxable and

non-taxable

investment securities:


	Three Months Ended September 30				Nine Months Ended September 30
(Dollars in Millions)	2019		2018		2019		2018
Taxable	$	683	$	605	$	2,023	$	1,763
Non-taxable		51		56		161		164
Total interest income from investment securities	$	734	$	661	$	2,184	$	1,927

The following table provides information about the amount of gross gains and losses realized through the sales of

available-for-sale

investment securities:


	Three Months Ended September 30				Nine Months Ended September 30
(Dollars in Millions)	2019		2018		2019			2018
Realized gains	$	25	$	10	$	66		$	25
Realized losses		–		–		(19	)		–
Net realized gains (losses)	$	25	$	10	$	47		$	25
Income tax (benefit) on net realized gains (losses)	$	6	$	2	$	12		$	6

The Company conducts a regular assessment of its investment securities with unrealized losses to determine whether investment securities are other-than-temporarily impaired considering, among other factors, the nature of the investment securities, the credit ratings or financial condition of the issuer, the extent and duration of the unrealized loss, expected cash flows of underlying collateral, the existence of any government or agency guarantees, market conditions and whether the Company intends to sell or it is more likely than not the Company will be required to sell the investment securities. The Company determines other-than-temporary impairment recorded in earnings for investment securities not intended to be sold by estimating the future cash flows of each individual investment security, using market information where available, and discounting the cash flows at the original effective rate of the investment security. Other-than-temporary impairment recorded in other comprehensive income (loss) is measured as the difference between that discounted amount and the fair value of each investment security. The total amount of other-than-temporary impairment recorded was immaterial for the three and nine months ended September 30, 2019 and 2018.

At September 30, 2019, certain investment sec

rities had a fair value below amortized cost. The following table shows the gross unrealized losses and fair value of the Company’s investment securities with unrealized losses, aggregated by investment category and length of time the individual investment securities have been in continuous unrealized loss positions, at

September 30, 2019:


	Less Than 12 Months					12 Months or Greater					Total
(Dollars in Millions)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Held-to-maturity
U.S. Treasury and agencies	$	954	$	(2	)	$	642	$	(5	)	$	1,596	$	(7	)
Residential agency mortgage-backed securities		4,610		(12	)		11,606		(150	)		16,216		(162	)
Other asset-backed securities		–		–			2		–			2		–
Other		8		–			–		–			8		–
Total held-to-maturity	$	5,572	$	(14	)	$	12,250	$	(155	)	$	17,822	$	(169	)
Available-for-sale
U.S. Treasury and agencies	$	2,313	$	(13	)	$	7,362	$	(34	)	$	9,675	$	(47	)
Residential agency mortgage-backed securities		4,377		(12	)		14,739		(190	)		19,116		(202	)
Commercial agency mortgage-backed securities		469		(5	)		–		–			469		(5	)
Obligations of state and political subdivisions		246		(2	)		2		–			248		(2	)
Total available-for-sale	$	7,405	$	(32	)	$	22,103	$	(224	)	$	29,508	$	(256	)

The Company does not consider these unrealized losses to be credit-related. These unrealized losses primarily relate to changes in interest rates and market spreads subsequent to purchase. A substantial portion of investment securities that have unrealized losses are either U.S. Treasury and agencies, agency mortgage-backed or state and political securities. In general, the issuers of the investment securities are contractually prohibited from prepayment at less than par, and the Company did not pay significant purchase premiums for these investment securities. At September 30, 2019, the Company had no plans to sell investment securities with unrealized losses, and believes it is more likely than not it would not be required to sell such investment securities before recovery of their amortized cost.