Investments (Tables)

3 Months Ended

Mar. 31, 2018

Investment [Line Items]

Schedule of short-term investments and cash equivalents

		March 31,		December 31,
(In millions)		2018		2017
Corporate securities	$	774	$	1,143
Federal government securities	$	226	$	604
Foreign government securities	$	191	$	159
Money market funds	$	12	$	12

Realized gains and losses on investments

	Three Months Ended
	March 31,
(In millions)	2018		2017
Fixed maturities	$	(20)	$	2
Equity securities		(19)		33
Other investments, including derivatives		6		11
Realized investment (losses) gains before income taxes		(33)		46
Less income tax (benefit) expense		(10)		15
Net realized investment (losses) gains	$	(23)	$	31

Sales information for available-for-sale fixed maturities and equity securities

	Three Months Ended
	March 31,
(In millions)	2018		2017
Proceeds from sales	$	499	$	414
Gross gains on sales	$	5	$	47
Gross losses on sales	$	22	$	2

Fixed Maturities [Member]

Investment [Line Items]

Investment maturities

		Amortized		Fair
(In millions)		Cost		Value
Due in one year or less	$	1,604	$	1,614
Due after one year through five years		6,798		6,923
Due after five years through ten years		10,455		10,416
Due after ten years		4,068		4,716
Mortgage and other asset-backed securities		491		509
Total fixed maturities	$	23,416	$	24,178

Gross unrealized appreciation (depreciation) on fixed maturities

				Gross		Gross
				Unrealized		Unrealized
		Amortized		Appre-		Depre-		Fair
(In millions)		Cost		ciation		ciation		Value
As of March 31, 2018
Federal government and agency	$	653	$	219	$	(4)	$	868
State and local government		1,058		72		(1)		1,129
Foreign government		2,402		119		(22)		2,499
Corporate		18,812		610		(249)		19,173
Mortgage and other asset-backed		491		23		(5)		509
Total fixed maturities	$	23,416	$	1,043	$	(281)	$	24,178
Investments supporting liabilities of the Company's run-off settlement annuity business (included in above total) (1)	$	2,241	$	576	$	(9)	$	2,808
As of December 31, 2017
Federal government and agency	$	541	$	239	$	(1)	$	779
State and local government		1,196		93		(2)		1,287
Foreign government		2,360		142		(15)		2,487
Corporate		17,301		868		(81)		18,088
Mortgage and other asset-backed		469		29		(1)		497
Total fixed maturities	$	21,867	$	1,371	$	(100)	$	23,138
Investments supporting liabilities of the Company's run-off settlement annuity business (included in above total) (1)	$	2,200	$	681	$	(2)	$	2,879
(1) Net unrealized appreciation for these investments is excluded from accumulated other comprehensive income.

Fixed maturities with a decline in fair value from amortized cost

	March 31, 2018							December 31, 2017
	Fair		Amortized		Unrealized		Number	Fair		Amortized		Unrealized		Number
(Dollars in millions)	Value		Cost		Depreciation		of Issues	Value		Cost		Depreciation		of Issues
One year or less
Investment grade	$	7,891	$	8,062	$	(171)	1,596	$	3,272	$	3,309	$	(37)	797
Below investment grade	$	1,058	$	1,080	$	(22)	1,096	$	543	$	553	$	(10)	643
More than one year
Investment grade	$	1,467	$	1,545	$	(78)	398	$	1,503	$	1,549	$	(46)	373
Below investment grade	$	148	$	158	$	(10)	47	$	155	$	162	$	(7)	42

Commercial Mortgage Loans [Member]

Investment [Line Items]

Credit risk profile of commercial mortgage loan portfolio

(Dollars in millions)	As of March 31, 2018				As of December 31, 2017
Loan-to-Value Ratio		Carrying Value	Average Debt Service Coverage Ratio	Average Loan-to-Value Ratio		Carrying Value	Average Debt Service Coverage Ratio	Average Loan-to-Value Ratio
Below 60%	$	1,182	2.04		$	1,109	2.03
60% to 79%		619	2.22			652	2.24
Total	$	1,801	2.10	57%	$	1,761	2.11	57%