Loans and Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
LGG loans	$ 541
LGG loans, repurchase liability	456
LGG loans, repossessed assets	14
Loans held-for-sale	1,182	$ 1,115
Loans reclassified to held-for-sale	360
Loans 90 days or greater past due and still accruing	0	0
Residential mortgage loans in process of foreclosure	81	121
Loans held for investment	83,627	68,608
Loans modified	262	$ 44
Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	25
Combination - Interest Rate Reduction & Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	10
One-to-four family first mortgage | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified that subsequently defaulted	4
One-to-four family first mortgage | Combination - Interest Rate Reduction & Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified that subsequently defaulted	4
Mortgage Loans | One-to-four family first mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	14
Mortgage Loans | One-to-four family first mortgage | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	5
Mortgage Loans | One-to-four family first mortgage | Combination - Interest Rate Reduction & Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	$ 6