Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Gross amounts recognized
Federal funds sold and security resell agreements	$ 1,714	$ 6,457
Derivatives (included in other assets)	285	418
Total assets	1,999	6,875
Federal funds purchased and other short-term borrowings	741	2,264
Derivatives (included in other liabilities)	44	38
Total liabilities	785	2,302
Gross amounts offset in the balance sheet
Federal funds sold and security resell agreements	0	(692)
Derivatives (included in other assets)	0	0
Total assets	0	(692)
Federal funds purchased and other short-term borrowings	0	(692)
Derivatives (included in other liabilities)	0	0
Total liabilities	0	(692)
Net amounts presented in the balance sheet
Federal funds sold and security resell agreements	1,714	5,765
Derivatives (included in other assets)	285	418
Total assets	1,999	6,183
Federal funds purchased and other short-term borrowings	741	1,572
Derivatives (included in other liabilities)	44	38
Total liabilities	785	1,610
Gross amounts not offset in the balance sheet, Financial Instruments
Federal funds sold and security resell agreements	0	0
Derivatives (included in other assets)	(15)	(4)
Total assets	(15)	(4)
Federal funds purchased and other short-term borrowings	0	0
Derivatives (included in other liabilities)	(15)	(4)
Total liabilities	(15)	(4)
Gross amounts not offset in the balance sheet, Cash collateral received/ pledged
Federal funds sold and security resell agreements	0	0
Derivatives (included in other assets)	(2)	(3)
Total assets	(2)	(3)
Federal funds purchased and other short-term borrowings	0	0
Derivatives (included in other liabilities)	(6)	(26)
Total liabilities	(6)	(26)
Net amount
Federal funds sold and security resell agreements	1,714	5,765
Derivatives (included in other assets)	268	411
Total assets	1,982	6,176
Federal funds purchased and other short-term borrowings	741	1,572
Derivatives (included in other liabilities)	23	8
Total liabilities	$ 764	$ 1,580