Investments (Tables)

12 Months Ended

Dec. 31, 2018

Amortized cost and fair value of investments in fixed maturities [Table Text Block]

The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows:



	Amortized		Gross Unrealized				Fair
(at December 31, 2018, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,076	$	4	$	16	$	2,064
Obligations of states, municipalities and political subdivisions:
Local general obligation	14,473		219		120		14,572
Revenue	9,755		172		74		9,853
State general obligation	1,329		18		13		1,334
Pre-refunded	2,772		80		—		2,852
Total obligations of states, municipalities and political subdivisions	28,329		489		207		28,611
Debt securities issued by foreign governments	1,255		7		5		1,257
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,557		54		38		2,573
All other corporate bonds	29,307		156		583		28,880
Redeemable preferred stock	77		2		—		79
Total	$	63,601	$	712	$	849	$	63,464



	Amortized		Gross Unrealized				Fair
(at December 31, 2017, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,080	$	4	$	8	$	2,076
Obligations of states, municipalities and political subdivisions:
Local general obligation	13,488		444		26		13,906
Revenue	11,307		338		19		11,626
State general obligation	1,443		44		3		1,484
Pre-refunded	3,758		142		1		3,899
Total obligations of states, municipalities and political subdivisions	29,996		968		49		30,915
Debt securities issued by foreign governments	1,505		14		10		1,509
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,334		87		11		2,410
All other corporate bonds	25,311		478		100		25,689
Redeemable preferred stock	90		5		—		95
Total	$	61,316	$	1,556	$	178	$	62,694

Amortized cost and fair value of fixed maturities by contractual maturity [Table Text Block]

The amortized cost and fair value of fixed maturities by contractual maturity follow. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



(at December 31, 2018, in millions)	Amortized Cost		Fair Value
Due in one year or less	$	4,489	$	4,505
Due after 1 year through 5 years	17,020		17,021
Due after 5 years through 10 years	17,030		16,785
Due after 10 years	22,505		22,580
	61,044		60,891
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,557		2,573
Total	$	63,601	$	63,464

Cost and fair value of investments in equity securities [Table Text Block]



(at December 31, 2018, in millions)	Cost		Gross Gains		Gross Losses		Fair Value
Public common stock	$	338	$	2	$	24	$	316
Non-redeemable preferred stock	44		8		—		52
Total	$	382	$	10	$	24	$	368

Cost and fair value of investments in equity securities classified as available for sale [Table Text Block]



(at December 31, 2017, in millions)	Cost		Gross Gains		Gross Losses		Fair Value
Public common stock	$	332	$	8	$	1	$	339
Non-redeemable preferred stock	108		12		6		114
Total	$	440	$	20	$	7	$	453

Unrealized investment losses [Table Text Block]

The following tables summarize, for all investments in an unrealized loss position at December 31, 2018 and 2017, 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. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1, in determining whether such investments are other-than-temporarily impaired.



	Less than 12 months				12 months or longer				Total
(at December 31, 2018, 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	$	484	$	5	$	1,011	$	11	$	1,495	$	16
Obligations of states, municipalities and political subdivisions	5,241		82		3,298		125		8,539		207
Debt securities issued by foreign governments	96		—		328		5		424		5
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	593		9		1,070		29		1,663		38
All other corporate bonds	12,622		303		6,872		280		19,494		583
Total fixed maturities	$	19,036	$	399	$	12,579	$	450	$	31,615	$	849



	Less than 12 months				12 months or longer				Total
(at December 31, 2017, 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	$	1,150	$	5	$	470	$	3	$	1,620	$	8
Obligations of states, municipalities and political subdivisions	505		2		2,959		47		3,464		49
Debt securities issued by foreign governments	394		6		111		4		505		10
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,021		7		250		4		1,271		11
All other corporate bonds	6,062		48		1,990		52		8,052		100
Total fixed maturities	9,132		68		5,780		110		14,912		178
Equity securities
Public common stock	18		—		34		1		52		1
Non-redeemable preferred stock	3		—		56		6		59		6
Total equity securities	21		—		90		7		111		7
Total	$	9,153	$	68	$	5,870	$	117	$	15,023	$	185

Impairment charges included in net realized investment gains [Table Text Block]

Impairment charges included in net realized investment gains in the consolidated statement of income were as follows:



(for the year ended December 31, in millions)	2018		2017		2016
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—
Obligations of states, municipalities and political subdivisions	—		—		—
Debt securities issued by foreign governments	—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	—		—		—
All other corporate bonds	1		4		15
Redeemable preferred stock	—		—		—
Total fixed maturities	1		4		15
Equity securities
Public common stock	—		9		9
Non-redeemable preferred stock	—		—		3
Total equity securities	—		9		12
Other investments	—		1		2
Total	$	1	$	14	$	29

Cumulative amount of and the changes during the year in the credit losses of other-than-temporary impairments (OTTI) on fixed maturities recognized [Table Text Block]

The following tables present the cumulative amount of and the changes during the year in credit losses on fixed maturities held at December 31, 2018 and 2017, that were recognized in the consolidated statement of income from other-than-temporary impairments (OTTI) and for which a portion of the OTTI was recognized in other comprehensive income (loss) in the consolidated balance sheet.



Year ended December 31, 2018 (in millions)	Cumulative OTTI Credit Losses Recognized for Securities Held, Beginning of Period		Additions for OTTI Securities Where No Credit Losses Were Previously Recognized		Additions for OTTI Securities Where Credit Losses Have Been Previously Recognized		Reductions Due to Sales/Defaults of Credit- Impaired Securities			Adjustments to Book Value of Credit- Impaired Securities due to Changes in Cash Flows		Cumulative OTTI Credit Losses Recognized for Securities Still Held, End of Period
Fixed maturities
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	$	29	$	—	$	—	$	(18	)	$	4	$	15
All other corporate bonds	46		—		—		(12		)	8		42
Total fixed maturities	$	75	$	—	$	—	$	(30	)	$	12	$	57



Year ended December 31, 2017 (in millions)	Cumulative OTTI Credit Losses Recognized for Securities Held, Beginning of Period		Additions for OTTI Securities Where No Credit Losses Were Previously Recognized		Additions for OTTI Securities Where Credit Losses Have Been Previously Recognized		Reductions Due to Sales/Defaults of Credit- Impaired Securities			Adjustments to Book Value of Credit- Impaired Securities due to Changes in Cash Flows			Cumulative OTTI Credit Losses Recognized for Securities Still Held, End of Period
Fixed maturities
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	$	31	$	—	$	—	$	—		$	(2	)	$	29
All other corporate bonds	54		—		1		(7		)	(2		)	46
Total fixed maturities	$	85	$	—	$	1	$	(7	)	$	(4	)	$	75

Net investment income [Table Text Block]



(for the year ended December 31, in millions)	2018		2017		2016
Gross investment income
Fixed maturities	$	1,980	$	1,895	$	1,981
Equity securities	16		28		37
Short-term securities	92		62		29
Real estate investments	48		44		51
Other investments	377		406		242
Gross investment income	2,513		2,435		2,340
Investment expenses	39		38		38
Net investment income	$	2,474	$	2,397	$	2,302

Change in net unrealized investments gains [Table Text Block]

Changes in net unrealized gains on investment securities that are included as a separate component of other comprehensive income (loss) were as follows:



(at and for the year ended December 31, in millions)	2018			2017			2016
Changes in net unrealized investment gains
Fixed maturities	$	(1,515	)	$	513		$	(915	)
Equity securities	—			(215		)	51
Other investments	(1		)	4			2
Change in net pre-tax unrealized gains on investment securities	(1,516		)	302			(862		)
Related tax expense (benefit)	(319		)	78			(303		)
Change in net unrealized gains on investment securities	(1,197		)	224			(559		)
Cumulative effect of adoption of updated accounting guidance for equity financial instruments at January 1, 2018	(22		)	—			—
Reclassification of certain tax effects from accumulated other comprehensive income at January 1, 2018	152			—			—
Balance, beginning of year	954			730			1,289
Balance, end of year	$	(113	)	$	954		$	730