Fair Value Measurements - Total Gains and Losses Included in Earning Attributable to Changes in Unrealized Gains and Losses Related to Level 3 Assets and Liabilities Still Held at Year End (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain and losses included in earnings	$ 42	$ 54	$ (20)	$ 273
Mortgage banking net revenue
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain and losses included in earnings	51	70	49	316
Commercial banking revenue
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain and losses included in earnings	1	1	3	3
Other noninterest income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain and losses included in earnings	$ (10)	$ (17)	$ (72)	$ (46)