Loans and Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
LGG loans	$ 563	$ 563
LGG loans, repurchase liability	362	362
LGG loans, repossessed assets	12	12
Loans held for sale, at fair value	1,926	1,926		$ 1,115
Loans reclassified to held-for-sale		360
Loans 90 days or greater past due and still accruing	0	0		0
Residential mortgage loans in process of foreclosure	92	92		$ 121
Loans modified	188	253	$ 45
Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	12	22
Combination - Interest Rate Reduction & Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	5	8
One-to-four family first mortgage | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified that subsequently defaulted		3
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		5
Mortgage Loans: | One-to-four family first mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	6	12
Mortgage Loans: | One-to-four family first mortgage | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	1	4
Mortgage Loans: | One-to-four family first mortgage | Combination - Interest Rate Reduction & Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified	$ 2	$ 5