Short-Term Borrowings and Long-Term Debt - Short-term and Long-term Credit Facilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) borrowings	Dec. 31, 2021 USD ($)
Short-term Debt [Line Items]
Short-term advances	$ 13,565	$ 71
Long-term debt	$ 5,370	2,570
Number of borrowings | borrowings	2
FHLB net weighted average fixed rate	4.69%
FHLB advances
Short-term Debt [Line Items]
Long-term debt	$ 2,000	0
FHLB advances
Short-term Debt [Line Items]
Short-term advances	13,000	0
FHLB advances	44,900	7,300
Amount of unused FHLB credit facility	25,900	$ 6,300
FRB advances
Short-term Debt [Line Items]
Line of credit, remaining borrowing capacity	5,300
Uncommitted federal funds lines
Short-term Debt [Line Items]
Line of credit, remaining borrowing capacity	$ 3,200