The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows:


	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized				Fair Value
(at March 31, 2023, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	6,617	$	—	$	18	$	283	$	6,352
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	18,866		—		74		1,430		17,510
Revenue	10,321		—		51		709		9,663
State general obligation	1,198		—		5		68		1,135
Pre-refunded	1,710		—		15		—		1,725
Total obligations of U.S. states, municipalities and political subdivisions	32,095		—		145		2,207		30,033
Debt securities issued by foreign governments	1,051		—		—		41		1,010
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	3,024		—		20		180		2,864
Corporate and all other bonds	35,040		4		71		2,452		32,655
Total	$	77,827	$	4	$	254	$	5,163	$	72,914


	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized				Fair Value
(at December 31, 2022, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	5,798	$	—	$	3	$	363	$	5,438
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	19,615		—		33		1,825		17,823
Revenue	11,076		—		29		907		10,198
State general obligation	1,104		—		3		88		1,019
Pre-refunded	2,323		—		17		1		2,339
Total obligations of U.S. states, municipalities and political subdivisions	34,118		—		82		2,821		31,379
Debt securities issued by foreign governments	1,049		—		—		55		994
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,178		—		13		200		1,991
Corporate and all other bonds	34,237		3		37		2,913		31,358
Total	$	77,380	$	3	$	135	$	6,352	$	71,160

Pre-refunded bonds of $1.73 billion and $2.34 billion at March 31, 2023 and December 31, 2022, respectively, were bonds for which U.S. states or municipalities have established irrevocable trusts that are almost exclusively comprised of U.S. Treasury securities and obligations of U.S. government and government agencies and authorities. These trusts were created to fund the payment of principal and interest due under the bonds.

Proceeds from the sales of fixed maturities classified as available for sale were $2.36 billion and $1.04 billion during the three months ended March 31, 2023 and 2022, respectively. Gross gains of $17 million and $5 million and gross losses of $27 million and $2 million were realized on those sales during the three months ended March 31, 2023 and 2022, respectively.

The cost and fair value of investments in equity securities were as follows:



(at March 31, 2023, in millions)	Cost		Gross Gains		Gross Losses		Fair Value
Common stock	$	549	$	79	$	25	$	603
Non-redeemable preferred stock	43		3		—		46
Total	$	592	$	82	$	25	$	649

For the three months ended March 31, 2023 and 2022, the Company recognized $17 million and $(14) million of net gains (losses) on equity securities still held as of March 31, 2023 and 2022, respectively.

The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at March 31, 2023 and December 31, 2022, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in note 4 herein and in note 4 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report to determine whether a credit loss impairment exists.


	Less than 12 months				12 months or longer				Total
(at March 31, 2023, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,056	$	29	$	1,969	$	254	$	4,025	$	283
Obligations of U.S. states, municipalities and political subdivisions	7,701		182		10,534		2,025		18,235		2,207
Debt securities issued by foreign governments	284		3		668		38		952		41
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	875		27		1,081		153		1,956		180
Corporate and all other bonds	14,709		441		15,098		2,011		29,807		2,452
Total	$	25,625	$	682	$	29,350	$	4,481	$	54,975	$	5,163


	Less than 12 months				12 months or longer				Total
(at December 31, 2022, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,835	$	100	$	1,679	$	263	$	4,514	$	363
Obligations of U.S. states, municipalities and political subdivisions	19,251		1,975		3,134		846		22,385		2,821
Debt securities issued by foreign governments	604		22		367		33		971		55
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,414		128		316		72		1,730		200
Corporate and all other bonds	24,080		1,635		6,096		1,278		30,176		2,913
Total	$	48,184	$	3,860	$	11,592	$	2,492	$	59,776	$	6,352

The following tables summarize, for all fixed maturities reported at fair value for which fair value was less than 80% of amortized cost at March 31, 2023 and December 31, 2022, the gross unrealized investment loss by length of time those securities have continuously been in an unrealized loss position of greater than 20% of amortized cost:


	Period For Which Fair Value is Less Than 80% of Amortized Cost
(at March 31, 2023, in millions)	3 months or less		Greater than 3 months, 6 months or less		Greater than 6 months, 12 months or less		Greater than 12 months		Total
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—	$	—	$	—
Obligations of U.S. states, municipalities and political subdivisions	115		1		617		185		918
Debt securities issued by foreign governments	—		—		—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	35		—		—		—		35
Corporate and all other bonds	103		1		84		—		188
Total	$	253	$	2	$	701	$	185	$	1,141


	Period For Which Fair Value is Less Than 80% of Amortized Cost
(at December 31, 2022, in millions)	3 months or less		Greater than 3 months, 6 months or less		Greater than 6 months, 12 months or less		Greater than 12 months		Total
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—	$	—	$	—
Obligations of U.S. states, municipalities and political subdivisions	81		776		643		—		1,500
Debt securities issued by foreign governments	1		—		—		—		1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	4		48		—		—		52
Corporate and all other bonds	89		526		8		—		623
Total	$	175	$	1,350	$	651	$	—	$	2,176

Recent increases in interest rates resulted in the gross unrealized investment losses disclosed in the table above; however, the net unrealized loss is considered temporary in nature as the decrease in value is not due to credit impairments and there is no impact on expected contractual cash flows from fixed maturities.

The following table presents changes in the allowance for expected credit losses on fixed maturities classified as available for sale for the category of Corporate and All Other Bonds (no other categories of fixed maturities currently have an allowance for expected credit losses):


	Fixed Maturities
	Corporate and All Other Bonds
	At and For the Three Months Ended
(in millions)	March 31, 2023		March 31, 2022

Balance, beginning of period	$	3	$	3
Additions for expected credit losses on securities where no credit losses were previously recognized	—		—
Additions for expected credit losses on securities where credit losses were previously recognized	1		1
Reductions due to sales/defaults of credit-impaired securities	—		—
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	—		—
Balance, end of period	$	4	$	4

Total net impairment charges, including credit impairments, reported in net realized investment gains (losses) in the consolidated statement of income, were $1 million for both the three months ended March 31, 2023 and 2022. Credit losses related to the fixed maturity portfolio for the three months ended March 31, 2023 and 2022 represented less than 1% of the fixed maturity portfolio on a pre-tax basis and less than 1% of shareholders’ equity on an after-tax basis.