Loans Held-for-Investment - Summary of Loans Held-for-Investment and UPB of Loan Sales and Purchases in the Loans Held-for-Investment Portfolio (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	$ 14,655		$ 13,408
Total loans sold	0	$ 87
Performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans sold	0	$ 87
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	4,181		3,385
Consumer loans | Residential first mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	2,205		1,536
Consumer loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	645		613
Consumer loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	1,331		1,236
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	10,474		10,023	$ 12,101
Commercial loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	3,387		3,223
Commercial loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	2,653		1,826
Commercial loans | Warehouse lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held-for-investment	$ 4,434		$ 4,974