
	2020						2019
In millions	Current		Long-term		Total		Current		Long-term		Total
Debt securities available for sale	$	2,774	$	18,414	$	21,188	$	2,251	$	14,671	$	16,922
Mortgage loans	226		821		1,047		122		1,091		1,213
Other investments	—		1,577		1,577		—		1,552		1,552
Total investments	$	3,000	$	20,812	$	23,812	$	2,373	$	17,314	$	19,687

At December 31, 2020 and 2019, the Company held investments of $524 million and $537 million, respectively, related to the 2012 conversion of an existing group annuity contract from a participating to a non-participating contract. The conversion occurred prior to the Aetna Acquisition. These investments are included in the total investments of large case pensions supporting non-experience-rated products. Although these investments are not accounted for as Separate Accounts assets, they are legally segregated and are not subject to claims that arise out of the Company’s business and only support future policy benefits obligations under that group annuity contract.


In millions	Amortized Cost (1)		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
December 31, 2020
Debt securities:
U.S. government securities	$	2,341	$	128	$	—	$	2,469
States, municipalities and political subdivisions	2,556		172		—		2,728
U.S. corporate securities	7,879		1,023		(8)		8,894
Foreign securities	2,595		324		(1)		2,918
Residential mortgage-backed securities	673		32		—		705
Commercial mortgage-backed securities	962		84		—		1,046
Other asset-backed securities	2,369		36		(2)		2,403
Redeemable preferred securities	21		4		—		25
Total debt securities (2)	$	19,396	$	1,803	$	(11)	$	21,188

December 31, 2019
Debt securities:
U.S. government securities	$	1,791	$	62	$	(1)	$	1,852
States, municipalities and political subdivisions	2,202		108		(1)		2,309
U.S. corporate securities	7,167		573		(3)		7,737
Foreign securities	2,149		200		(1)		2,348
Residential mortgage-backed securities	508		25		—		533
Commercial mortgage-backed securities	654		46		—		700
Other asset-backed securities	1,397		13		(5)		1,405
Redeemable preferred securities	30		8		—		38
Total debt securities (2)	$	15,898	$	1,035	$	(11)	$	16,922

(1)Effective January 1, 2020, the Company adopted the available-for-sale debt security impairment model under ASU 2016-13, Financial Instruments -Credit Losses (Topic 326). The new impairment model requires the write down of amortized cost through an allowance for credit losses, rather than through a reduction of the amortized cost basis of the available-for-sale debt security. There was no allowance for credit losses recorded on available-for-sale debt securities at December 31, 2020. As the Company adopted the new available-for-sale debt security impairment model on a prospective basis, there was no allowance for credit losses recorded on available-for-sale debt securities at December 31, 2019.

(2)Investment risks associated with the Company’s experience-rated products generally do not impact the Company’s consolidated operating results. At December 31, 2020, debt securities with a fair value of $919 million, gross unrealized capital gains of $135 million and no gross unrealized capital losses and at December 31, 2019, debt securities with a fair value of $965 million, gross unrealized capital gains of $83 million and no gross unrealized capital losses were included in total debt securities, but support experience-rated products. Changes in net unrealized capital gains (losses) on these securities are not reflected in accumulated other comprehensive income.

The amortized cost and fair value of debt securities at December 31, 2020 are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company intends to sell a security prior to maturity.


In millions	Amortized Cost		Fair Value
Due to mature:
Less than one year	$	1,276	$	1,291
One year through five years	6,346		6,698
After five years through ten years	3,748		4,121
Greater than ten years	4,022		4,924
Residential mortgage-backed securities	673		705
Commercial mortgage-backed securities	962		1,046
Other asset-backed securities	2,369		2,403
Total	$	19,396	$	21,188

All of the Company’s residential mortgage-backed securities at December 31, 2020 were issued by the Government National Mortgage Association, the Federal National Mortgage Association or the Federal Home Loan Mortgage Corporation and carry agency guarantees and explicit or implicit guarantees by the U.S. Government. At December 31, 2020, the Company’s residential mortgage-backed securities had an average credit quality rating of AAA and a weighted average duration of 2.4 years.

The Company’s commercial mortgage-backed securities have underlying loans that are dispersed throughout the United States. Significant market observable inputs used to value these securities include loss severity and probability of default. At December 31, 2020, these securities had an average credit quality rating of AAA and a weighted average duration of 6.1 years.

The Company’s other asset-backed securities have a variety of underlying collateral (e.g., automobile loans, credit card receivables, home equity loans and commercial loans). Significant market observable inputs used to value these securities include the unemployment rate, loss severity and probability of default. At December 31, 2020, these securities had an average credit quality rating of AA and a weighted average duration of 1.1 years.


	Less than 12 months					Greater than 12 months					Total
In millions, except number of securities	Number of Securities	Fair Value		Unrealized Losses		Number of Securities	Fair Value		Unrealized Losses		Number of Securities	Fair Value		Unrealized Losses
December 31, 2020
Debt securities:
U.S. government securities	32	$	205	$	—	—	$	—	$	—	32	$	205	$	—
States, municipalities and political subdivisions	49	83		—		—	—		—		49	83		—
U.S. corporate securities	145	155		8		2	—		—		147	155		8
Foreign securities	41	69		1		5	5		—		46	74		1
Residential mortgage-backed securities	23	26		—		3	—		—		26	26		—
Commercial mortgage-backed securities	22	75		—		—	—		—		22	75		—
Other asset-backed securities	156	256		1		49	41		1		205	297		2
Total debt securities	468	$	869	$	10	59	$	46	$	1	527	$	915	$	11

December 31, 2019
Debt securities:
U.S. government securities	52	$	168	$	1	—	$	—	$	—	52	$	168	$	1
States, municipalities and political subdivisions	66	115		1		2	5		—		68	120		1
U.S. corporate securities	181	305		2		2	—		1		183	305		3
Foreign securities	39	75		1		—	—		—		39	75		1
Residential mortgage-backed securities	30	16		—		9	—		—		39	16		—
Commercial mortgage-backed securities	16	49		—		—	—		—		16	49		—
Other asset-backed securities	138	254		1		187	182		4		325	436		5

Total debt securities	522	$	982	$	6	200	$	187	$	5	722	$	1,169	$	11

The Company reviewed the securities in the table above and concluded that they are performing assets generating investment income to support the needs of the Company’s business. In performing this review, the Company considered factors such as the quality of the investment security based on research performed by the Company’s internal credit analysts and external rating agencies and the prospects of realizing the carrying value of the security based on the investment’s current prospects for recovery. As of December 31, 2020, the Company did not intend to sell these securities, and did not believe it was more likely than not that it would be required to sell these securities prior to the anticipated recovery of their amortized cost basis.


	Supporting experience- rated products				Supporting remaining products				Total
In millions	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Due to mature:
Less than one year	$	—	$	—	$	9	$	—	$	9	$	—
One year through five years	—		—		300		4		300		4
After five years through ten years	4		—		165		4		169		4
Greater than ten years	3		—		36		1		39		1
Residential mortgage-backed securities	—		—		26		—		26		—
Commercial mortgage-backed securities	2		—		73		—		75		—
Other asset-backed securities	5		—		292		2		297		2
Total	$	14	$	—	$	901	$	11	$	915	$	11

The Company assesses mortgage loans on a regular basis for credit impairments, and assigns a credit quality indicator to each loan. The Company’s credit quality indicator is internally developed and categorizes each loan in its portfolio on a scale from 1 to 7. These indicators are based upon several factors, including current loan-to-value ratios, current and future property cash flow, property condition, market trends, creditworthiness of the borrower and deal structure.


	Amortized Cost Basis by Year of Origination
In millions, except credit quality indicator	2020		2019		2018		2017		2016		Prior		Total
December 31, 2020
1	$	—	$	—	$	—	$	22	$	—	$	37	$	59
2 to 4	46		96		91		124		101		494		952
5 and 6	—		—		3		4		—		29		36
7	—		—		—		—		—		—		—
Total	$	46	$	96	$	94	$	150	$	101	$	560	$	1,047

December 31, 2019
1			$	—	$	—	$	15	$	—	$	43	$	58
2 to 4			93		93		206		140		611		1,143
5 and 6			—		—		—		—		12		12
7			—		—		—		—		—		—
Total			$	93	$	93	$	221	$	140	$	666	$	1,213


In millions	2020		2019		2018
Debt securities	$	598	$	589	$	61
Mortgage loans	60		71		6
Other investments	123		194		593
Gross investment income	781		854		660
Investment expenses	(35)		(42)		(3)
Net investment income (excluding net realized capital gains or losses)	746		812		657
Net realized capital gains (1)	52		199		3
Net investment income (2)	$	798	$	1,011	$	660

(1)Net realized capital gains are net of yield-related impairment losses on debt securities of $49 million for the year ended December 31, 2020. There were no credit-related losses on debt securities in the year ended December 31, 2020. Net realized capital gains are net of other-than-temporary impairment (“OTTI”) losses on debt securities of $24 million for the year ended December 31, 2019. There were no material OTTI losses on debt securities for the year ended December 31, 2018.

Excluding amounts related to experience-rated products, proceeds from the sale of available for sale debt securities and the related gross realized capital gains and losses in the years ended December 31, 2020, 2019 and subsequent to the Aetna Acquisition Date in 2018 were as follows: