Investment securities principally include available-for-sale debt securities carried at fair value on the Consolidated Balance Sheets. Unrealized losses attributable to credit deterioration are recorded in the Consolidated Statements of Income in Other loans Provision for credit losses. Unrealized gains and any portion of a security’s unrealized loss attributable to non-credit losses are recorded in the Consolidated Statements of Comprehensive Income, net of tax. We had accrued interest on our available-for-sale debt securities totaling $12 million as of both September 30, 2023 and December 31, 2022, presented as Other assets on the Consolidated Balance Sheets.

Investment securities also include equity securities carried at fair value on the Consolidated Balance Sheets with unrealized gains and losses recorded in the Consolidated Statements of Income as Other, net expense.

Realized gains and losses are recognized upon disposition of the securities using the specific identification method and recorded in the Consolidated Statements of Income as Other, net expense.

The following is a summary of investment securities as of September 30, 2023 and December 31, 2022:


	2023								2022
Description of Securities (Millions)	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale debt securities:
State and municipal obligations	$	62	$	—	$	(10)	$	52	$	64	$	—	$	(10)	$	54
U.S. Government agency obligations	4		—		—		4		5		—		—		5
U.S. Government treasury obligations (a)	2,214		—		(27)		2,187		3,859		—		(73)		3,786
Mortgage-backed securities (b)	12		—		(1)		11		13		—		—		13
Foreign government bonds and obligations	777		—		(1)		776		633		—		(1)		632
Other (c)	64		—		—		64		47		—		—		47
Equity securities (d)(e)	60		20		(14)		66		50		—		(9)		41
Total	$	3,193	$	20	$	(53)	$	3,160	$	4,671	$	—	$	(93)	$	4,578

(a)Excludes approximately $1 billion of U.S. Government treasury obligations that matured on September 30, 2023, for which cash was received on October 2, 2023. As of September 30, 2023, these investments were derecognized and a corresponding receivable was recorded in Other assets on the Consolidated Balance Sheets; this non-cash movement is not reflected in the Consolidated Statements of Cash Flows.

(e)During the third quarter of 2023, certain equity securities were reclassified from Other assets to Investment securities following the completion of transactions pursuant to which the issuers of the securities became public companies. The investments had a fair value of $26 million with an associated cost basis of $10 million as of September 30, 2023. The gross unrealized gain and loss amounts include net unrealized gains of $37 million that were recognized prior to such transactions.

The following table provides information about our available-for-sale debt securities with gross unrealized losses and the length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2023 and December 31, 2022:


	2023								2022
	Less than 12 months				12 months or more				Less than 12 months				12 months or more
Description of Securities (Millions)	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
State and municipal obligations	$	20	$	(1)	$	30	$	(9)	$	52	$	(10)	$	—	$	—
U.S. Government treasury obligations	—		—		2,098		(27)		3,710		(72)		52		(1)
Mortgage-backed securities	—		—		7		(1)		—		—		—		—
Foreign government bonds and obligations	679		(1)		—		—		549		(1)		—		—
Total	$	699	$	(2)	$	2,135	$	(37)	$	4,311	$	(83)	$	52	$	(1)

The gross unrealized losses on our available-for-sale debt securities are primarily attributable to an increase in the current benchmark interest rate. Overall, for the available-for-sale debt securities in gross unrealized loss positions, (i) we do not intend to sell the securities, (ii) it is more likely than not that we will not be required to sell the securities before recovery of the unrealized losses, and (iii) we expect that the contractual principal and interest will be received on the securities. We concluded that there was no credit loss attributable to the securities in an unrealized loss position for the periods presented.

The following table summarizes the gross unrealized losses for available-for-sale debt securities by ratio of fair value to amortized cost as of September 30, 2023 and December 31, 2022:


	Less than 12 months					12 months or more					Total
Ratio of Fair Value to Amortized Cost (Dollars in millions)	Number of Securities	Estimated Fair Value		Gross Unrealized Losses		Number of Securities	Estimated Fair Value		Gross Unrealized Losses		Number of Securities	Estimated Fair Value		Gross Unrealized Losses
2023:
90–100%	53	$	699	$	(2)	44	$	2,107	$	(27)	97	$	2,806	$	(29)
Less than 90%	—	$	—	$	—	32	$	28	$	(10)	32	$	28	$	(10)
Total as of September 30, 2023	53	$	699	$	(2)	76	$	2,135	$	(37)	129	$	2,834	$	(39)
2022:
90–100%	74	$	4,287	$	(74)	3	$	52	$	(1)	77	$	4,339	$	(75)
Less than 90%	14	$	24	$	(9)	—	$	—	$	—	14	$	24	$	(9)
Total as of December 31, 2022	88	$	4,311	$	(83)	3	$	52	$	(1)	91	$	4,363	$	(84)


(Millions)	Cost		Estimated Fair Value
Due within 1 year	$	2,804	$	2,784
Due after 1 year but within 5 years	233		226
Due after 5 years but within 10 years	40		39
Due after 10 years	56		45
Total	$	3,133	$	3,094

The expected payments on state and municipal obligations, U.S. Government agency obligations and mortgage-backed securities may not coincide with their contractual maturities because the issuers have the right to call or prepay certain obligations.