Fair Value of Assets and Liabilities - Schedule of Nonrecurring Fair Value Measurements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	$ 68	$ 51
Loans and leases	61,292	58,102
Non Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases	245	135	$ 84
Other real estate owned (OREO)	4	3	3
Other assets	90	91	80
Net gains (losses) loans	(42)	(19)	(13)
Net gains (losses) other real estate owned	0	0	(1)
Net gains (losses) other assets	(7)	(10)	(7)
Net gains (losses) financial assets	(52)	(32)	(23)
Non Recurring | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale			1
Net gains (losses) loans held-for-sale			0
Non Recurring | SBAs and USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	406	506	853
Net gains (losses) loans held-for-sale	(3)	(3)	(2)
Non Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases	0	0	0
Other real estate owned (OREO)	0	0	0
Other assets	0	0	0
Non Recurring | Level 1 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale			0
Non Recurring | Level 1 | SBAs and USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	0	0	0
Non Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases	0	0	0
Other real estate owned (OREO)	0	0	0
Other assets	0	0	0
Non Recurring | Level 2 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale			0
Non Recurring | Level 2 | SBAs and USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	406	506	852
Non Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases	245	135	84
Other real estate owned (OREO)	4	3	3
Other assets	90	91	80
Non Recurring | Level 3 | First Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale			1
Non Recurring | Level 3 | SBAs and USDA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	$ 0	$ 0	$ 1