The following realized gains and losses on investments exclude amounts required to adjust future policy benefits for the run-off settlement annuity business:

	Three Months Ended
	March 31,
(In millions)	2015		2014
Fixed maturities	$	7	$	8
Equity securities		13		17
Commercial mortgage loans		5		-
Other investments, including derivatives		48		17
Realized investment gains before income taxes		73		42
Less income taxes		25		15
Net realized investment gains	$	48	$	27

Included in these realized investment gains (losses) were pre-tax asset write-downs as follows:

	Three Months Ended
	March 31,
(In millions)	2015		2014
Credit-related (1)	$	(6)	$	(6)
Other		(5)		-
Total	$	(11)	$	(6)

(1) Credit-related losses are due to asset write-downs related to investments in real estate entities.

Sales information for available-for-sale fixed maturities and equity securities was as follows:

The amortized cost and fair value by contractual maturity periods for fixed maturities were as follows at March 31, 2015:

		Amortized		Fair
(In millions)		Cost		Value
Due in one year or less	$	1,065	$	1,081
Due after one year through five years		5,736		6,123
Due after five years through ten years		6,537		6,981
Due after ten years		3,299		4,247
Mortgage and other asset-backed securities		615		709
Total	$	17,252	$	19,141

Actual maturities of these securities could differ from their contractual maturities used in the table above. This could occur because issuers may have the right to call or prepay obligations, with or without penalties, or because in certain cases the Company may have the option to unilaterally extend the contractual maturity date.

Gross unrealized appreciation (depreciation) on fixed maturities by type of issuer is shown below.

				Gross		Gross
				Unrealized		Unrealized
		Amortized		Appre-		Depre-		Fair
		Cost		ciation		ciation		Value
(In millions)	March 31, 2015
Federal government and agency	$	568	$	355	$	-	$	923
State and local government		1,662		172		(2)		1,832
Foreign government		1,807		153		(4)		1,956
Corporate		12,600		1,159		(38)		13,721
Mortgage-backed		62		3		(1)		64
Other asset-backed		553		94		(2)		645
Total	$	17,252	$	1,936	$	(47)	$	19,141

(In millions)	December 31, 2014
Federal government and agency	$	608	$	346	$	-	$	954
State and local government		1,682		176		(2)		1,856
Foreign government		1,824		121		(5)		1,940
Corporate		12,517		1,014		(33)		13,498
Mortgage-backed		83		3		(1)		85
Other asset-backed		564		87		(1)		650
Total	$	17,278	$	1,747	$	(42)	$	18,983

The above table includes investments with a fair value of $3.2 billion supporting the Company's run-off settlement annuity business, with gross unrealized appreciation of $820 million and gross unrealized depreciation of $3 million at March 31, 2015. Such unrealized amounts are reported in future policy benefit liabilities rather than accumulated other comprehensive income. At December 31, 2014, investments supporting this business had a fair value of $3.1 billion, gross unrealized appreciation of $758 million and gross unrealized depreciation of $2 million.

Review of declines in fair value. Management reviews fixed maturities with a decline in fair value from cost for impairment based on criteria that include:

The table below summarizes fixed maturities with a decline in fair value from amortized cost as of March 31, 2015. These fixed maturities are primarily corporate securities with a decline in fair value that reflects an increase in market yields since purchase.

	March 31, 2015

	Fair		Amortized		Unrealized		Number
(Dollars in millions)	Value		Cost		Depreciation		of Issues
Fixed maturities:
One year or less:
Investment grade	$	695	$	712	$	(17)	139
Below investment grade	$	245	$	262	$	(17)	143
More than one year:
Investment grade	$	146	$	151	$	(5)	64
Below investment grade	$	76	$	84	$	(8)	24

There were no available for sale equity securities with a significant unrealized loss reflected in accumulated other comprehensive income at March 31, 2015. Equity securities also include hybrid investments consisting of preferred stock with call features that are carried at fair value with changes in fair value reported in other realized investment gains (losses) and dividends reported in net investment income. As of March 31, 2015, fair values of these securities were $61 million and amortized cost was $72 million. As of December 31, 2014, fair values of these securities were $57 million and amortized cost was $69 million.

Mortgage loans held by the Company are made exclusively to commercial borrowers and are diversified by property type, location and borrower. Loans are generally issued at a fixed rate of interest and are secured by high quality, primarily completed and substantially leased operating properties.

Credit quality. The Company regularly evaluates and monitors credit risk, beginning with the initial underwriting of a mortgage loan and continuing throughout the investment holding period. Mortgage origination professionals employ an internal credit quality rating system designed to evaluate the relative risk of the transaction at origination that is then updated each year as part of the annual portfolio loan review. The Company evaluates and monitors credit quality on an ongoing basis, classifying each loan as a loan in good standing, potential problem loan or problem loan.

Quality ratings are based on our evaluation of a number of key inputs related to the loan, including real estate market-related factors such as rental rates and vacancies, and property-specific inputs such as growth rate assumptions and lease rollover statistics. However, the two most significant contributors to the credit quality rating are the debt service coverage and loan-to-value ratios. The debt service coverage ratio measures the amount of property cash flow available to meet annual interest and principal payments on debt, with a ratio below 1.0 indicating that there is not enough cash flow to cover the required loan payments. The loan-to-value ratio, commonly expressed as a percentage, compares the amount of the loan to the fair value of the underlying property collateralizing the loan.

The following tables summarize the credit risk profile of the Company's commercial mortgage loan portfolio based on loan-to-value and debt service coverage ratios, as of March 31, 2015 and December 31, 2014:

(In millions)				March 31, 2015
		Debt Service Coverage Ratio
		1.30x or		1.20x to		1.10x to		1.00x to		Less than
Loan-to-Value Ratios		Greater		1.29x		1.19x		1.09x		1.00x		Total
Below 50%	$	338	$	18	$	-	$	6	$	-	$	362
50% to 59%		638		37		-		-		-		675
60% to 69%		457		-		15		-		60		532
70% to 79%		68		36		32		-		79		215
80% to 89%		6		41		-		-		62		109
90% to 100%		-		-		55		-		62		117
Total	$	1,507	$	132	$	102	$	6	$	263	$	2,010

(In millions)					December 31, 2014
		Debt Service Coverage Ratio
		1.30x or		1.20x to		1.10x to		1.00x to		Less than
Loan-to-Value Ratios		Greater		1.29x		1.19x		1.09x		1.00x		Total
Below 50%	$	340	$	17	$	-	$	6	$	-	$	363
50% to 59%		681		38		-		-		-		719
60% to 69%		394		-		15		-		60		469
70% to 79%		68		36		33		-		80		217
80% to 89%		6		41		-		-		58		105
90% to 100%		-		-		55		-		153		208
Total	$	1,489	$	132	$	103	$	6	$	351	$	2,081

The Company's annual in-depth review of its commercial mortgage loan investments is the primary mechanism for identifying emerging risks in the portfolio. The most recent review was completed by the Company's investment professionals in the second quarter of 2014 and included an analysis of each underlying property's most recent annual financial statements, rent rolls, operating plans, budgets, a physical inspection of the property and other pertinent factors. Based on historical results, current leases, lease expirations and rental conditions in each market, the Company estimates the current year and future stabilized property income and fair value, and categorizes the investments as loans in good standing, potential problem loans or problem loans. Based on property valuations and cash flows estimated as part of this review, and considering updates for loans where material changes were subsequently identified, the portfolio's average loan-to-value ratio improved to 61% at March 31, 2015 from 63% at December 31, 2014. The portfolio's average debt service coverage ratio was estimated to be 1.70 at March 31, 2015, an improvement from 1.66 at December 31, 2014.

The Company reevaluates a loan's credit quality between annual reviews if new property information is received or an event such as delinquency or a borrower's request for restructure causes management to believe that the Company's estimate of financial performance, fair value or the risk profile of the underlying property has been affected.

Potential problem mortgage loans are considered current (no payment is more than 59 days past due), but exhibit certain characteristics that increase the likelihood of future default. The characteristics management considers include, but are not limited to, the deterioration of debt service coverage below 1.0, estimated loan-to-value ratios increasing to 100% or more, downgrade in quality rating and requests from the borrower for restructuring. In addition, loans are considered potential problems if principal or interest payments are past due by more than 30 but less than 60 days. Problem mortgage loans are either in default by 60 days or more or have been restructured as to terms, which could include concessions on interest rate, principal payment or maturity date. The Company monitors each problem and potential problem mortgage loan on an ongoing basis, and updates the loan categorization and quality rating when warranted.

Problem and potential problem mortgage loans, net of valuation reserves, totaled $134 million at March 31, 2015 and $208 million at December 31, 2014.

Impaired commercial mortgage loans. A commercial mortgage loan is considered impaired when it is probable that the Company will not collect all amounts due according to the terms of the original loan agreement. These loans are included in either problem or potential problem loans. The Company monitors credit risk and assesses the impairment of loans individually and on a consistent basis for all loans in the portfolio. Impaired loans are carried at the lower of unpaid principal balance or the fair value of the underlying real estate. Certain commercial mortgage loans without valuation reserves are considered impaired because the Company will not collect all interest due according to the terms of the original agreements; however, the Company expects to recover the unpaid principal because it is less than the fair value of the underlying real estate.

The carrying value of the Company's impaired commercial mortgage loans and related valuation reserves were as follows:

(In millions)		March 31, 2015					December 31, 2014
		Gross		Reserves		Net		Gross		Reserves		Net
Impaired commercial mortgage loans with valuation reserves	$	83	$	(8)	$	75	$	147	$	(12)	$	135
Impaired commercial mortgage loans with no valuation reserves		31		-		31		31		-		31
Total	$	114	$	(8)	$	106	$	178	$	(12)	$	166

The average recorded investment in impaired loans was $146 million during the three months ended March 31, 2015 and $120 million during the three months ended March 31, 2014. Because of the risk profile of the underlying investment, the Company recognizes interest income on problem mortgage loans only when payment is actually received. Interest income that would have been reflected in net income if interest on non-accrual commercial mortgage loans had been received in accordance with the original terms was not significant for the three months ended March 31, 2015 or 2014. Interest income on impaired commercial mortgage loans was not significant for the three months ended March 31, 2015 or 2014.

Changes in valuation reserves for commercial mortgage loans were not material for the three months ended March 31, 2015 and 2014.

Short-term investments and cash equivalents include corporate securities of $1.6 billion, federal government securities of $151 million and money market funds of $41 million as of March 31, 2015. The Company's short-term investments and cash equivalents as of December 31, 2014 included corporate securities of $509 million, federal government securities of $274 million and money market funds of $33 million.