Fair Value (Schedule of Assets and Liabilities Measured at Fair Value by Class on a Recurring Basis Using Level 3 Inputs) (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Private equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value of assets, Beginning balance	$ 74	$ 83	$ 66	$ 80
Unrealized securities gains (losses), net	0	68	5	69
Other noninterest income (expense)	0	0	0	0
Purchases	3	2	9	6
Cost of investments sold	0	(4)	(3)	(6)
Transfers out	0	(77)	0	(77)
Fair value of assets, Ending balance	77	72	77	72
Ag loan servicing & interest only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value of assets, Beginning balance	12	15	12	16
Unrealized securities gains (losses), net	0	0	0	0
Other noninterest income (expense)	0	0	0	(1)
Purchases	0	0	0	0
Cost of investments sold	0	0	0	0
Transfers out	0	0	0	0
Fair value of assets, Ending balance	$ 12	$ 15	$ 12	$ 15