Investment Securities (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Estimated Fair Value
Estimated Fair Value, Due within 1 year	$ 1,477
Estimated Fair Value, Due after 1 year but within 5 years	900
Estimated Fair Value, Due after 5 years but within 10 years	41
Estimated Fair Value, Due after 10 years	94
Total	2,512
Available For Sale Securities Debt Maturities Amortized Cost [Abstract]
Due within 1 year	1,476
Due after 1 year but within 5 years	879
Due after 5 years but within 10 years	35
Due after 10 years	92
Available-for-sale debt securities, Cost	$ 2,482
Weighted average yields
Weighted average yields, due within 1 year	1.74%
Weighted average yields, due after 1 years but within 5 years	2.42%
Weighted average yields, due after 5 years but within 10 years	5.46%
Weighted average yield, due after 10 years	3.10%
Weighted average yields, Total	2.08%
Combined tax at U.S. statutory federal income tax rate (as a percent)	21.00%	21.00%	21.00%
State and municipal obligations
Estimated Fair Value
Estimated Fair Value, Due within 1 year	$ 6
Estimated Fair Value, Due after 1 year but within 5 years	5
Estimated Fair Value, Due after 5 years but within 10 years	30
Estimated Fair Value, Due after 10 years	70
Total	111
U.S. Government agency obligations
Estimated Fair Value
Estimated Fair Value, Due within 1 year	0
Estimated Fair Value, Due after 1 year but within 5 years	0
Estimated Fair Value, Due after 5 years but within 10 years	0
Estimated Fair Value, Due after 10 years	6
Total	6
U.S. Government treasury obligations
Estimated Fair Value
Estimated Fair Value, Due within 1 year	832
Estimated Fair Value, Due after 1 year but within 5 years	862
Estimated Fair Value, Due after 5 years but within 10 years	10
Estimated Fair Value, Due after 10 years	0
Total	1,704
Mortgage-backed securities
Estimated Fair Value
Estimated Fair Value, Due within 1 year	0
Estimated Fair Value, Due after 1 year but within 5 years	0
Estimated Fair Value, Due after 5 years but within 10 years	0
Estimated Fair Value, Due after 10 years	18
Total	18
Foreign government bonds and obligations
Estimated Fair Value
Estimated Fair Value, Due within 1 year	628
Estimated Fair Value, Due after 1 year but within 5 years	1
Estimated Fair Value, Due after 5 years but within 10 years	1
Estimated Fair Value, Due after 10 years	0
Total	630
Other
Estimated Fair Value
Estimated Fair Value, Due within 1 year	11
Estimated Fair Value, Due after 1 year but within 5 years	32
Estimated Fair Value, Due after 5 years but within 10 years	0
Estimated Fair Value, Due after 10 years	0
Total	$ 43