Investments in Debt and Equity Securities (Details 2) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	$ 1,219	$ 2,203
Less than 12 months - Unrealized losses	27	70
12 months or more - Fair Value	1,352	585
12 months or more - Unrealized losses	99	78
Total - Fair Value	2,571	2,788
Total - Unrealized losses	126	148
Other U.S. and non-U.S. government bonds
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	13	19
Less than 12 months - Unrealized losses	1	1
12 months or more - Fair Value	26	20
12 months or more - Unrealized losses	4	4
Total - Fair Value	39	39
Total - Unrealized losses	5	5
Corporate bonds
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	990	1,815
Less than 12 months - Unrealized losses	19	46
12 months or more - Fair Value	931	357
12 months or more - Unrealized losses	61	50
Total - Fair Value	1,921	2,172
Total - Unrealized losses	80	96
Asset-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	67	75
Less than 12 months - Unrealized losses	2	2
12 months or more - Fair Value	86	55
12 months or more - Unrealized losses	4	3
Total - Fair Value	153	130
Total - Unrealized losses	6	5
U.S. governmental agency mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	107	229
Less than 12 months - Unrealized losses	3	16
12 months or more - Fair Value	226	98
12 months or more - Unrealized losses	22	15
Total - Fair Value	333	327
Total - Unrealized losses	25	31
Residential
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value		2
Less than 12 months - Unrealized losses		0
12 months or more - Fair Value		1
12 months or more - Unrealized losses		1
Total - Fair Value		3
Total - Unrealized losses		1
Commercial
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months - Fair Value	42	63
Less than 12 months - Unrealized losses	2	5
12 months or more - Fair Value	83	54
12 months or more - Unrealized losses	8	5
Total - Fair Value	125	117
Total - Unrealized losses	$ 10	$ 10