Investment Securities (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Accrued interest available-for-sale debt securities	$ 15	$ 12
Available-for-sale debt securities:
Cost	4,587
Estimated Fair Value	4,496
Equity securities
Cost	53	66
Gross Unrealized Gains	0	17
Gross Unrealized Losses	(10)	(4)
Estimated Fair Value	43	79
Total Cost	4,640	2,548
Total Gross Unrealized Gains	0	48
Total Gross Unrealized Losses	(101)	(5)
Total Estimated Fair Value	4,539	2,591
State and municipal obligations
Available-for-sale debt securities:
Cost	66	106
Gross Unrealized Gains	0	5
Gross Unrealized Losses	(11)	0
Estimated Fair Value	55	111
U.S. Government agency obligations
Available-for-sale debt securities:
Cost	5	6
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	5	6
U.S. Government treasury obligations
Available-for-sale debt securities:
Cost	3,844	1,680
Gross Unrealized Gains	0	25
Gross Unrealized Losses	(77)	(1)
Estimated Fair Value	3,767	1,704
Mortgage-backed securities
Available-for-sale debt securities:
Cost	13	17
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Estimated Fair Value	13	18
Foreign government bonds and obligations
Available-for-sale debt securities:
Cost	627	630
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	0
Estimated Fair Value	624	630
Other
Available-for-sale debt securities:
Cost	32	43
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 32	$ 43