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 June 30, 2022, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	3,845	$	—	$	7	$	264	$	3,588
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	19,959		—		55		1,593		18,421
Revenue	11,174		—		38		763		10,449
State general obligation	1,169		—		6		75		1,100
Pre-refunded	3,566		—		72		—		3,638
Total obligations of U.S. states, municipalities and political subdivisions	35,868		—		171		2,431		33,608
Debt securities issued by foreign governments	1,048		—		1		47		1,002
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,795		—		15		120		1,690
Corporate and all other bonds	33,361		4		32		2,178		31,211
Total	$	75,917	$	4	$	226	$	5,040	$	71,099


	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized				Fair Value
(at December 31, 2021, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	3,574	$	—	$	20	$	32	$	3,562
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	18,668		—		1,045		46		19,667
Revenue	11,274		—		693		27		11,940
State general obligation	1,158		—		67		2		1,223
Pre-refunded	3,825		—		207		—		4,032
Total obligations of U.S. states, municipalities and political subdivisions	34,925		—		2,012		75		36,862
Debt securities issued by foreign governments	1,041		—		7		7		1,041
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,754		—		68		5		1,817
Corporate and all other bonds	33,457		3		1,249		175		34,528
Total	$	74,751	$	3	$	3,356	$	294	$	77,810

Pre-refunded bonds of $3.64 billion and $4.03 billion at June 30, 2022 and December 31, 2021, 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 $2.70 billion and $2.48 billion during the six months ended June 30, 2022 and 2021, respectively. Gross gains of $10 million and $43 million and gross losses of $8 million and $5 million were realized on those sales during the six months ended June 30, 2022 and 2021, respectively.

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


							Fair
(at June 30, 2022, in millions)	Cost		Gross Gains		Gross Losses		Value
Common stock	$	706	$	66	$	27	$	745
Non-redeemable preferred stock	49		8		2		55
Total	$	755	$	74	$	29	$	800

For the six months ended June 30, 2022 and 2021, the Company recognized $(85) million and $51 million of net gains (losses) on equity securities still held as of June 30, 2022 and 2021, respectively.

The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at June 30, 2022 and December 31, 2021, 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 2021 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 2021 Annual Report to determine whether a credit loss impairment exists.


	Less than 12 months				12 months or longer				Total
(at June 30, 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	$	2,506	$	235	$	221	$	29	$	2,727	$	264
Obligations of U.S. states, municipalities and political subdivisions	19,690		2,201		1,117		230		20,807		2,431
Debt securities issued by foreign governments	805		34		136		13		941		47
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,476		118		21		2		1,497		120
Corporate and all other bonds	25,489		1,818		1,917		360		27,406		2,178
Total	$	49,966	$	4,406	$	3,412	$	634	$	53,378	$	5,040


	Less than 12 months				12 months or longer				Total
(at December 31, 2021, 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	$	2,438	$	32	$	5	$	—	$	2,443	$	32
Obligations of U.S. states, municipalities and political subdivisions	3,873		69		153		6		4,026		75
Debt securities issued by foreign governments	452		7		7		—		459		7
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	426		5		1		—		427		5
Corporate and all other bonds	7,306		153		436		22		7,742		175
Total	$	14,495	$	266	$	602	$	28	$	15,097	$	294

The following table summarizes, for all fixed maturities reported at fair value for which fair value is less than 80% of amortized cost at June 30, 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 June 30, 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	807		195		—		—		1,002
Debt securities issued by foreign governments	—		—		—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	—		—		—		—		—
Corporate and all other bonds	116		—		—		—		116
Total	$	923	$	195	$	—	$	—	$	1,118

At December 31, 2021, the Company had no fixed maturity investments reported at fair value for which fair value was less than 80% of amortized cost. The increase in fixed maturities in an unrealized loss position from December 31, 2021 through June 30, 2022 was primarily due to higher interest rates. These unrealized losses at June 30, 2022 represented less than 2% of the fixed maturity portfolio on a pre-tax basis and approximately 5% of shareholders' equity on an after-tax basis.

The following tables present 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
(in millions)	At and For the Three Months Ended June 30, 2022		At and For the Three Months Ended June 30, 2021

Balance, beginning of period	$	4	$	2
Additions for expected credit losses on securities where no credit losses were previously recognized	—		1
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	—		(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	$	2


	Fixed Maturities
	Corporate and All Other Bonds
(in millions)	At and For the Six Months Ended June 30, 2022		At and For the Six Months Ended June 30, 2021

Balance, beginning of period	$	3		$	2
Additions for expected credit losses on securities where no credit losses were previously recognized	—			1
Additions (reductions) 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		$	2

Total net impairment charges, including credit impairments, reported in net realized investment gains (losses) in the consolidated statement of income, were $20 million and $0 million for the three months ended June 30, 2022 and 2021, respectively, and $21 million and $0 million for the six months ended June 30, 2022 and 2021, respectively. Credit losses related to the fixed maturity portfolio for both the three months and six months ended June 30, 2022 and 2021 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.