Investment Securities (Details 2) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Less than 12 months	$ 3,038	$ 477
Gross Unrealized Losses, Less than 12 months	(17)	(1)
State and municipal obligations
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Less than 12 months	44	0
Gross Unrealized Losses, Less than 12 months	(4)	0
U.S. Government treasury obligations
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Less than 12 months	2,554	477
Gross Unrealized Losses, Less than 12 months	(12)	(1)
Foreign government bonds and obligations
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value, Less than 12 months	440	0
Gross Unrealized Losses, Less than 12 months	$ (1)	$ 0