Investments (Tables)

12 Months Ended

Dec. 31, 2023

Investments [Abstract]

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		Allowance for Expected Credit Losses		Gross Unrealized				Fair
(at December 31, 2023, in millions)	Cost				Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	6,591	$	—	$	8	$	231	$	6,368
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	18,374		—		90		1,265		17,199
Revenue	9,748		—		52		616		9,184
State general obligation	1,209		—		7		59		1,157
Pre-refunded	963		—		5		2		966
Total obligations of U.S. states, municipalities and political subdivisions	30,294		—		154		1,942		28,506
Debt securities issued by foreign governments	1,035		—		2		31		1,006
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	7,874		—		120		176		7,818
Corporate and all other bonds	35,987		5		187		2,060		34,109
Total	$	81,781	$	5	$	471	$	4,440	$	77,807

	Amortized		Allowance for Expected Credit Losses		Gross Unrealized				Fair
(at December 31, 2022, in millions)	Cost				Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	5,798	$	—	$	3	$	363	$	5,438
Obligations of U.S. states, municipalities and political subdivisions:
Local general obligation	19,615		—		33		1,825		17,823
Revenue	11,076		—		29		907		10,198
State general obligation	1,104		—		3		88		1,019
Pre-refunded	2,323		—		17		1		2,339
Total obligations of U.S. states, municipalities and political subdivisions	34,118		—		82		2,821		31,379
Debt securities issued by foreign governments	1,049		—		—		55		994
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,178		—		13		200		1,991
Corporate and all other bonds	34,237		3		37		2,913		31,358
Total	$	77,380	$	3	$	135	$	6,352	$	71,160

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, 2023, in millions)	Amortized Cost		Fair Value
Due in one year or less	$	5,004	$	4,965
Due after 1 year through 5 years	25,328		24,592
Due after 5 years through 10 years	21,407		19,740
Due after 10 years	22,168		20,692
	73,907		69,989
Mortgage-backed securities, collateralized mortgage obligations  and pass-through securities	7,874		7,818
Total	$	81,781	$	77,807

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

The cost and fair value of investments in equity securities were as follows:

(at December 31, 2023, in millions)	Cost		Gross Gains		Gross Losses		Fair Value
Common stock	$	508	$	93	$	41	$	560
Non-redeemable preferred stock	45		3		—		48
Total	$	553	$	96	$	41	$	608

(at December 31, 2022, in millions)	Cost		Gross Gains		Gross Losses		Fair Value
Common stock	$	706	$	89	$	32	$	763
Non-redeemable preferred stock	41		3		—		44
Total	$	747	$	92	$	32	$	807

Unrealized investment losses [Table Text Block]

The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at December 31, 2023 and 2022, the aggregate fair value and gross unrealized loss by the 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 a credit loss impairment exists.

	Less than 12 months				12 months or longer				Total
(at December 31, 2023, 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	$	1,864	$	7	$	2,985	$	224	$	4,849	$	231
Obligations of U.S. states, municipalities and political subdivisions	3,868		31		14,351		1,911		18,219		1,942
Debt securities issued by foreign governments	30		—		763		31		793		31
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,215		9		1,433		167		2,648		176
Corporate and all other bonds	1,016		9		26,444		2,051		27,460		2,060
Total	$	7,993	$	56	$	45,976	$	4,384	$	53,969	$	4,440

	Less than 12 months				12 months or longer				Total
(at December 31, 2022, 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	$	2,835	$	100	$	1,679	$	263	$	4,514	$	363
Obligations of U.S. states, municipalities and political subdivisions	19,251		1,975		3,134		846		22,385		2,821
Debt securities issued by foreign governments	604		22		367		33		971		55
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,414		128		316		72		1,730		200
Corporate and all other bonds	24,080		1,635		6,096		1,278		30,176		2,913
Total	$	48,184	$	3,860	$	11,592	$	2,492	$	59,776	$	6,352

Gross unrealized investment losses on securities continuously in an unrealized loss position of greater than 20% of amortized cost by length of time [Table Text Block]

The following tables summarize, for all fixed maturities reported at fair value for which fair value was less than 80% of amortized cost at December 31, 2023 and December 31, 2022, the gross unrealized investment loss by length of time those securities have continuously been in an unrealized loss position of greater than 20% of amortized cost:

	Period For Which Fair Value is Less Than 80% of Amortized Cost
(at December 31, 2023, in millions)	3 months or less		Greater than 3 months, 6 months or less		Greater than 6 months, 12 months or less		Greater than 12 months		Total
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—	$	—	$	—
Obligations of U.S. states, municipalities and political subdivisions	—		2		31		642		675
Debt securities issued by foreign governments	—		—		—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	—		—		—		—		—
Corporate and all other bonds	1		3		22		25		51
Total	$	1	$	5	$	53	$	667	$	726

	Period For Which Fair Value is Less Than 80% of Amortized Cost
(at December 31, 2022, in millions)	3 months or less		Greater than 3 months, 6 months or less		Greater than 6 months, 12 months or less		Greater than 12 months		Total
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—	$	—	$	—
Obligations of U.S. states, municipalities and political subdivisions	81		776		643		—		1,500
Debt securities issued by foreign governments	1		—		—		—		1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	4		48		—		—		52
Corporate and all other bonds	89		526		8		—		623
Total	$	175	$	1,350	$	651	$	—	$	2,176

Credit impairment charges included in net realized investment gains (losses) [Table Text Block]

Credit impairment charges included in net realized investment gains (losses) in the consolidated statement of income were as follows:

(for the year ended December 31, in millions)	2023		2022		2021
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	12	$	—
Obligations of U.S. states, municipalities and political subdivisions	1		14		—
Debt securities issued by foreign governments	—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	—		—		—
Corporate and all other bonds	2		—		2
Total fixed maturities	$	3	$	26	$	2

Changes in the allowance for expected credit losses on fixed maturities classified as available for sale [Table Text Block]

The following table presents changes in the allowance for expected credit losses on fixed maturities classified as available for sale for the category of Corporate and All Other Bonds (no other categories of fixed maturities currently have an allowance for expected credit losses):

	Fixed Maturities
	Corporate and All Other Bonds
(in millions)	At and For the Twelve Months Ended December 31, 2023		At and For the Twelve Months Ended December 31, 2022
Balance, beginning of period	$	3	$	3
Additions for expected credit losses on securities where no credit losses were previously recognized	1		—
Additions for expected credit losses on securities where credit losses were previously recognized	1		1
Reductions due to sales/defaults of credit-impaired securities	—		(1)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	—		—
Balance, end of period	$	5	$	3

Net investment income [Table Text Block]

(for the year ended December 31, in millions)	2023		2022		2021
Gross investment income
Fixed maturities	$	2,472	$	2,113	$	1,989
Equity securities	18		17		19
Short-term securities	241		73		7
Real estate investments	64		66		59
Other investments	171		336		999
Gross investment income	2,966		2,605		3,073
Investment expenses	44		43		40
Net investment income	$	2,922	$	2,562	$	3,033

Change in net unrealized investments gains (losses) [Table Text Block]

Changes in net unrealized gains (losses) 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)	2023		2022		2021
Changes in net unrealized investment gains (losses)
Fixed maturities	$	2,248	$	(9,279)	$	(2,113)
Other investments	2		(1)		(2)
Change in net pre-tax unrealized gains (losses) on investment securities	2,250		(9,280)		(2,115)
Related tax expense (benefit)	481		(1,967)		(456)
Change in net unrealized gains (losses) on investment securities	1,769		(7,313)		(1,659)
Balance, beginning of year	(4,898)		2,415		4,074
Balance, end of year	$	(3,129)	$	(4,898)	$	2,415