Fair Value Measures - Assets Measured at Fair Value on a Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Loans held for investment	$ 3,166	$ 2,469
Loans held for sale	23	335
Other assets	43	52
Total assets at fair value	3,232	2,856
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Loans held for investment	0	0
Loans held for sale	0	0
Other assets	0	0
Total assets at fair value	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Loans held for investment	0	0
Loans held for sale	23	335
Other assets	0	0
Total assets at fair value	23	335
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Loans held for investment	3,166	2,469
Loans held for sale	0	0
Other assets	43	52
Total assets at fair value	$ 3,209	$ 2,521