
	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized						Fair Value
(at September 30, 2020, in millions)							Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,083	$	—	$	43	$	—	$	2,126
Obligations of states, municipalities and political subdivisions:
Local general obligation	17,019		—		1,267		8		18,278
Revenue	11,871		—		829		6		12,694
State general obligation	1,160		—		91		—		1,251
Pre-refunded	2,458		—		160		—		2,618
Total obligations of states, municipalities and political subdivisions	32,508		—		2,347		14		34,841
Debt securities issued by foreign governments	952		—		27		—		979
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,572		—		158		—		2,730
All other corporate bonds	29,599		4		2,314		35		31,874
Redeemable preferred stock	22		—		2		—		24
Total	$	67,736	$	4	$	4,891	$	49	$	72,574


	Amortized		Gross Unrealized						Fair
(at December 31, 2019, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,076	$	19	$	—	$	2,095
Obligations of states, municipalities and political subdivisions:
Local general obligation	15,490		829		4		16,315
Revenue	9,731		586		2		10,315
State general obligation	1,167		64		—		1,231
Pre-refunded	1,968		88		—		2,056
Total obligations of states, municipalities and political subdivisions	28,356		1,567		6		29,917
Debt securities issued by foreign governments	1,167		8		2		1,173
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	3,192		91		3		3,280
All other corporate bonds	30,442		1,195		18		31,619
Redeemable preferred stock	48		2		—		50
Total	$	65,281	$	2,882	$	29	$	68,134

Pre-refunded bonds of $2.62 billion and $2.06 billion at September 30, 2020 and December 31, 2019, respectively, were bonds for which states or municipalities have established irrevocable trusts, 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 sales of fixed maturities classified as available for sale were $1.99 billion and $1.80 billion during the nine months ended September 30, 2020 and 2019, respectively. Gross gains of $52 million and $51 million and gross losses of $3 million and $6 million were realized on those sales during the nine months ended September 30, 2020 and 2019, respectively.


									Fair
(at September 30, 2020, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	346	$	44	$	22	$	368
Non-redeemable preferred stock	35		8		1		42
Total	$	381	$	52	$	23	$	410


									Fair
(at December 31, 2019, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	341	$	45	$	3	$	383
Non-redeemable preferred stock	35		7		—		42
Total	$	376	$	52	$	3	$	425

For the nine months ended September 30, 2020 and 2019, the Company recognized $(14) million and $49 million of net gains (losses) on equity securities still held as of September 30, 2020 and 2019, respectively. Net realized investment losses on equity securities still held for the first nine months of 2020 were driven by the impact of changes in fair value attributable to the volatility in global financial markets associated with the global pandemic beginning in March 2020 related to the novel coronavirus COVID-19.

The following tables summarize, for all investments in an unrealized loss position at September 30, 2020 and December 31, 2019, the aggregate fair value and gross unrealized loss by 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 notes to the consolidated financial statements in the Company’s 2019 Annual Report. The Company also relies upon estimates of several credit and non-credit factors in its review and evaluation of individual investments, using the process described in note 1 of notes to the consolidated financial statements to determine whether credit impairment exists.


	Less than 12 months						12 months or longer						Total
(at September 30, 2020, 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	$	169	$	—	$	—	$	—	$	169	$	—
Obligations of states, municipalities and political subdivisions	1,751		14		—		—		1,751		14
Debt securities issued by foreign governments	14		—		—		—		14		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	11		—		1		—		12		—
All other corporate bonds	1,095		28		120		7		1,215		35

Total	$	3,040	$	42	$	121	$	7	$	3,161	$	49


	Less than 12 months						12 months or longer						Total
(at December 31, 2019, 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	$	5	$	—	$	193	$	—	$	198	$	—
Obligations of states, municipalities and political subdivisions	668		6		12		—		680		6
Debt securities issued by foreign governments	257		1		147		1		404		2
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	399		2		131		1		530		3
All other corporate bonds	1,571		10		662		8		2,233		18
Total	$	2,900	$	19	$	1,145	$	10	$	4,045	$	29

At September 30, 2020, the amount of gross unrealized losses for all fixed maturity investments reported at fair value for which fair value was less than 80% of amortized cost was not significant.


	Fixed Maturities
(for the three months ended September 30, 2020 in millions)	Mortgage-Backed Securities, Collateralized Mortgage Obligations and Pass-Through Securities		All Other Corporate Bonds		Total

Balance, July 1, 2020	$	—	$	8	$	8
Additions for expected credit losses on securities where no credit losses were previously recognized	—		1		1
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	—		(3)		(3)
Reductions due to sales/defaults of credit-impaired securities	—		(2)		(2)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell ⁽¹⁾	—		—		—
Balance, September 30, 2020	$	—	$	4	$	4


	Fixed Maturities
(for the nine months ended September 30, 2020 in millions)	Mortgage-Backed Securities, Collateralized Mortgage Obligations and Pass-Through Securities		All Other Corporate Bonds		Total

Balance, January 1, 2020	$	—	$	—	$	—
Additions for expected credit losses on securities where no credit losses were previously recognized	—		9		9
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	—		(3)		(3)
Reductions due to sales/defaults of credit-impaired securities	—		(2)		(2)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell ⁽¹⁾	—		—		—
Balance, September 30, 2020	$	—	$	4	$	4

(1)Credit impairment charges recognized in net realized investment gains (losses) for the nine months ended September 30, 2020 included $14 million of credit losses on fixed maturity securities which the Company intends to sell. An allowance for expected credit losses was not previously recorded for these securities.

Total net credit impairment charges (recoveries) included in net realized investment gains (losses) in the consolidated statement of income were $(4) million and $0 million for the three months ended September 30, 2020 and 2019, respectively, and $58 million and $2 million for the nine months ended September 30, 2020 and 2019, respectively. Additionally, net realized investment gains (losses) in the first nine months of 2020 included $40 million of realized losses related to the other-than-temporary impairment of the carrying value of an equity method investment included in other investments. Credit losses related to the fixed maturity portfolio for the three months and nine months ended September 30, 2020 and 2019 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 at both September 30, 2020 and 2019.