
	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized				Fair Value
(at March 31, 2021, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,530	$	—	$	32	$	18	$	2,544
Obligations of states, municipalities and political subdivisions:
Local general obligation	17,719		—		1,079		84		18,714
Revenue	11,748		—		699		44		12,403
State general obligation	1,337		—		81		4		1,414
Pre-refunded	3,365		—		204		—		3,569
Total obligations of states, municipalities and political subdivisions	34,169		—		2,063		132		36,100
Debt securities issued by foreign governments	962		—		18		4		976
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,939		—		107		1		2,045
All other corporate bonds	30,663		2		1,651		141		32,171
Redeemable preferred stock	23		—		2		—		25
Total	$	70,286	$	2	$	3,873	$	296	$	73,861


	Amortized Cost		Allowance for Expected Credit Losses		Gross Unrealized				Fair Value
(at December 31, 2020, in millions)					Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,111	$	—	$	38	$	—	$	2,149
Obligations of states, municipalities and political subdivisions:
Local general obligation	17,289		—		1,370		2		18,657
Revenue	11,806		—		909		—		12,715
State general obligation	1,343		—		101		—		1,444
Pre-refunded	3,325		—		219		—		3,544
Total obligations of states, municipalities and political subdivisions	33,763		—		2,599		2		36,360
Debt securities issued by foreign governments	1,028		—		26		—		1,054
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,222		—		139		—		2,361
All other corporate bonds	29,683		2		2,382		9		32,054
Redeemable preferred stock	23		—		2		—		25
Total	$	68,830	$	2	$	5,186	$	11	$	74,003

Pre-refunded bonds of $3.57 billion and $3.54 billion at March 31, 2021 and December 31, 2020, 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 $1.24 billion and $388 million during the three months ended March 31, 2021 and 2020, respectively. Gross gains of $15 million and gross losses of $1 million were realized on those sales during each of the three months ended March 31, 2021 and 2020.


							Fair
(at March 31, 2021, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	352	$	87	$	7	$	432
Non-redeemable preferred stock	35		10		—		45
Total	$	387	$	97	$	7	$	477


							Fair
(at December 31, 2020, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	352	$	70	$	12	$	410
Non-redeemable preferred stock	35		8		—		43
Total	$	387	$	78	$	12	$	453

For the three months ended March 31, 2021 and 2020, the Company recognized $23 million and $(79) million of net gains (losses) on equity securities still held as of March 31, 2021 and 2020, respectively. Net realized losses on equity securities still held for the first quarter of 2020 were driven by the impact of changes in fair value attributable to the disruption in global financial markets associated with the global pandemic beginning in March 2020.

The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at March 31, 2021 and December 31, 2020, 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 2020 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 notes to the consolidated financial statements in the Company’s 2020 Annual Report to determine whether a credit loss impairment exists.


	Less than 12 months				12 months or longer				Total
(at March 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	$	854	$	18	$	—	$	—	$	854	$	18
Obligations of states, municipalities and political subdivisions	4,654		132		—		—		4,654		132
Debt securities issued by foreign governments	158		4		—		—		158		4
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	50		1		1		—		51		1
All other corporate bonds	3,494		137		125		4		3,619		141

Total	$	9,210	$	292	$	126	$	4	$	9,336	$	296


	Less than 12 months				12 months or longer				Total
(at December 31, 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	$	92	$	—	$	—	$	—	$	92	$	—
Obligations of states, municipalities and political subdivisions	245		2		—		—		245		2
Debt securities issued by foreign governments	7		—		—		—		7		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	20		—		1		—		21		—
All other corporate bonds	681		6		97		3		778		9
Total	$	1,045	$	8	$	98	$	3	$	1,143	$	11

At March 31, 2021, 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 March 31, 2021, in millions)	Mortgage-Backed Securities, Collateralized Mortgage Obligations and Pass-Through Securities		All Other Corporate Bonds		Total

Balance, December 31, 2020	$	—	$	2	$	2
Additions for expected credit losses on securities where no credit losses were previously recognized	—		—		—
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	—		—		—
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 (1)	—		—		—
Balance, March 31, 2021	$	—	$	2	$	2

(1)Credit impairment charges recognized in net realized investment gains (losses) for the three months ended March 31, 2021 included no credit losses on fixed maturity securities which the Company had the intent to sell.


	Fixed Maturities
(for the twelve months ended December 31, 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	—		10		10
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	—		(6)		(6)
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, December 31, 2020	$	—	$	2	$	2

(1)Credit impairment charges recognized in net realized investment gains for the twelve months ended December 31, 2020 included $13 million of credit losses on fixed maturity securities which the Company had the intent 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 $0 million and $16 million for the three months ended March 31, 2021 and 2020, respectively. Credit losses related to the fixed maturity portfolio for the three months ended March 31, 2021 and 2020 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.