Investments in Debt and Equity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Schedule of Investments in Debt and Equity Securities
Cost basis	$ 2,714	$ 1,694
Unrealized pretax net gains (losses)	(52)	27
Fair Value	2,662	1,721
U.S. treasury bonds
Schedule of Investments in Debt and Equity Securities
Cost basis	9	10
Unrealized pretax net gains (losses)	0	0
Fair Value	9	10
Other U.S. and non-U.S. government bonds
Schedule of Investments in Debt and Equity Securities
Cost basis	61	61
Unrealized pretax net gains (losses)	(1)	0
Fair Value	60	61
Corporate bonds
Schedule of Investments in Debt and Equity Securities
Cost basis	2,026	1,027
Unrealized pretax net gains (losses)	(38)	19
Fair Value	1,988	1,046
Asset-backed securities
Schedule of Investments in Debt and Equity Securities
Cost basis	184	175
Unrealized pretax net gains (losses)	(1)	1
Fair Value	183	176
U.S. governmental agency mortgage-backed securities
Schedule of Investments in Debt and Equity Securities
Cost basis	328	319
Unrealized pretax net gains (losses)	(9)	6
Fair Value	319	325
Residential
Schedule of Investments in Debt and Equity Securities
Cost basis	3	4
Unrealized pretax net gains (losses)	0	0
Fair Value	3	4
Commercial
Schedule of Investments in Debt and Equity Securities
Cost basis	103	98
Unrealized pretax net gains (losses)	(3)	1
Fair Value	$ 100	$ 99