Investments (Tables)

12 Months Ended

Dec. 31, 2023

Short-Term and Long-Term Investments [Table Text Block]

A summary of debt securities by major security type is as follows:


(in millions)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
December 31, 2023
Debt securities - available-for-sale:
U.S. government and agency obligations	$	4,674	$	3	$	(234)	$	4,443
State and municipal obligations	7,636		39		(322)		7,353
Corporate obligations	23,136		67		(1,186)		22,017
U.S. agency mortgage-backed securities	8,982		22		(708)		8,296
Non-U.S. agency mortgage-backed securities	3,023		3		(240)		2,786
Total debt securities - available-for-sale	47,451		134		(2,690)		44,895
Debt securities - held-to-maturity:
U.S. government and agency obligations	506		1		(6)		501
State and municipal obligations	28		—		(2)		26
Corporate obligations	69		—		—		69
Total debt securities - held-to-maturity	603		1		(8)		596
Total debt securities	$	48,054	$	135	$	(2,698)	$	45,491
December 31, 2022
Debt securities - available-for-sale:
U.S. government and agency obligations	$	4,093	$	1	$	(285)	$	3,809
State and municipal obligations	7,702		25		(479)		7,248
Corporate obligations	23,675		17		(1,798)		21,894
U.S. agency mortgage-backed securities	7,379		15		(808)		6,586
Non-U.S. agency mortgage-backed securities	3,077		1		(294)		2,784
Total debt securities - available-for-sale	45,926		59		(3,664)		42,321
Debt securities - held-to-maturity:
U.S. government and agency obligations	578		—		(14)		564
State and municipal obligations	29		—		(3)		26
Corporate obligations	89		—		—		89
Total debt securities - held-to-maturity	696		—		(17)		679
Total debt securities	$	46,622	$	59	$	(3,681)	$	43,000

Investments by Contractual Maturity [Table Text Block]

The amortized cost and fair value of debt securities as of December 31, 2023, by contractual maturity, were as follows:


	Available-for-Sale				Held-to-Maturity
(in millions)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	4,286	$	4,260	$	313	$	310
Due after one year through five years	15,124		14,556		246		244
Due after five years through ten years	10,844		10,036		26		25
Due after ten years	5,192		4,961		18		17
U.S. agency mortgage-backed securities	8,982		8,296		—		—
Non-U.S. agency mortgage-backed securities	3,023		2,786		—		—
Total debt securities	$	47,451	$	44,895	$	603	$	596

Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value

The fair value of available-for-sale debt securities with gross unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position were as follows:


	Less Than 12 Months				12 Months or Greater				Total
(in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
December 31, 2023
U.S. government and agency obligations	$	1,270	$	(7)	$	2,077	$	(227)	$	3,347	$	(234)
State and municipal obligations	907		(7)		4,063		(315)		4,970		(322)
Corporate obligations	1,826		(17)		14,696		(1,169)		16,522		(1,186)
U.S. agency mortgage-backed securities	1,337		(12)		5,069		(696)		6,406		(708)
Non-U.S. agency mortgage-backed securities	279		(6)		2,202		(234)		2,481		(240)
Total debt securities - available-for-sale	$	5,619	$	(49)	$	28,107	$	(2,641)	$	33,726	$	(2,690)
December 31, 2022
U.S. government and agency obligations	$	2,007	$	(96)	$	1,290	$	(189)	$	3,297	$	(285)
State and municipal obligations	4,630		(288)		1,178		(191)		5,808		(479)
Corporate obligations	13,003		(893)		6,637		(905)		19,640		(1,798)
U.S. agency mortgage-backed securities	3,561		(345)		2,239		(463)		5,800		(808)
Non-U.S. agency mortgage-backed securities	1,698		(128)		976		(166)		2,674		(294)
Total debt securities - available-for-sale	$	24,899	$	(1,750)	$	12,320	$	(1,914)	$	37,219	$	(3,664)