Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments [Abstract]

Analysis Of Cost Or Amortized Cost, Gross Unrealized Gains And Losses And Fair Value for Investments

The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our fixed-maturity and equity securities:

(Dollars in millions)	Cost or amortized cost		Gross unrealized				Fair value
At December 31, 2017			gains		losses
Fixed-maturity securities:
Corporate	$	5,420	$	246	$	13	$	5,653
States, municipalities and political subdivisions	4,316		155		6		4,465
Commercial mortgage-backed	280		7		1		286
Government-sponsored enterprises	257		1		4		254
United States government	31		—		—		31
Foreign government	10		—		—		10
Subtotal	10,314		409		24		10,699
Equity securities:
Common equities	2,918		3,135		14		6,039
Nonredeemable preferred equities	176		34		—		210
Subtotal	3,094		3,169		14		6,249
Total	$	13,408	$	3,578	$	38	$	16,948
At December 31, 2016
Fixed-maturity securities:
Corporate	$	5,555	$	252	$	26	$	5,781
States, municipalities and political subdivisions	3,770		100		42		3,828
Commercial mortgage-backed	282		7		2		287
Government-sponsored enterprises	167		—		3		164
United States government	10		—		—		10
Foreign government	10		—		—		10
Convertibles and bonds with warrants attached	5		—		—		5
Subtotal	9,799		359		73		10,085
Equity securities:
Common equities	2,812		2,320		9		5,123
Nonredeemable preferred equities	183		28		—		211
Subtotal	2,995		2,348		9		5,334
Total	$	12,794	$	2,707	$	82	$	15,419

Fair Values And Unrealized Losses by Investment Category And By The Duration Of The Securities' Continuous Unrealized Loss Position

The table below provides fair values and unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss positions:

(Dollars in millions)	Less than 12 months				12 months or more				Total
At December 31, 2017	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Fixed-maturity securities:
Corporate	$	330	$	4	$	252	$	9	$	582	$	13
States, municipalities and political subdivisions	88		1		264		5		352		6
Commercial mortgage-backed	33		—		36		1		69		1
Government-sponsored enterprises	96		1		124		3		220		4
Foreign government	10		—		—		—		10		—
United States government	23		—		6		—		29		—
Subtotal	580		6		682		18		1,262		24
Equity securities:
Common equities	229		14		—		—		229		14
Subtotal	229		14		—		—		229		14
Total	$	809	$	20	$	682	$	18	$	1,491	$	38
At December 31, 2016
Fixed-maturity securities:
Corporate	$	733	$	15	$	189	$	11	$	922	$	26
States, municipalities and political subdivisions	989		42		—		—		989		42
Commercial mortgage-backed	89		2		2		—		91		2
Government-sponsored enterprises	155		3		—		—		155		3
United States government	6		—		—		—		6		—
Subtotal	1,972		62		191		11		2,163		73
Equity securities:
Common equities	103		9		—		—		103		9
Nonredeemable preferred equities	4		—		—		—		4		—
Subtotal	107		9		—		—		107		9
Total	$	2,079	$	71	$	191	$	11	$	2,270	$	82

Contractual Maturity Dates For Fixed-Maturity And Short-Term Investments

Contractual maturity dates for fixed-maturity investments were:

(Dollars in millions)	Amortized cost		Fair value		% of fair value
At December 31, 2017
Maturity dates:
Due in one year or less	$	511	$	519	4.9	%
Due after one year through five years	2,736		2,839		26.5
Due after five years through ten years	3,921		4,058		37.9
Due after ten years	3,146		3,283		30.7
Total	$	10,314	$	10,699	100.0	%

Investment Income, Realized Investment Gains And Losses And Change In Unrealized Investment Gains And Losses

The following table provides investment income and realized investment gains and losses:

(Dollars in millions)	Years ended December 31,
	2017			2016			2015
Investment income:
Interest	$	445		$	440		$	428
Dividends	170			161			150
Other	4			3			3
Total	619			604			581
Less investment expenses	10			9			9
Total	$	609		$	595		$	572
Realized investment gains and losses:
Fixed maturities:
Gross realized gains	$	25		$	26		$	18
Gross realized losses	—			(1		)	—
Other-than-temporary impairments	(6		)	(2		)	(18		)
Equity securities:
Gross realized gains	195			152			129
Gross realized losses	(72		)	(53		)	(26		)
Other-than-temporary impairments	(3		)	—			(34		)
Other	9			2			1
Total	$	148		$	124		$	70