Fair Value Measurement - Nonrecurring Fair Value Measurements (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 1,200	$ 347
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	0	0
Loans held for sale	431	515
Other investments	1,329	1,329
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	302,943	308,044
Loans held for sale	0	0
Other investments	0	0
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	361	545
Loans held for sale	10	37
Other assets	86	214
Total	457	796
Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	0	0
Loans held for sale	10	37
Other assets	0	0
Total	10	37
Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	361	545
Loans held for sale	0	0
Other assets	86	214
Total	447	759
Equity investments accounted for under measurement alternative	31	46
Foreclosed property and repossessed assets, fair value disclosure	$ 55	45
Long lived assets held for sale		$ 123