Parent Company Financial Statements - Condensed Statements of Income - Parent Company Only (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income
Dividends from consolidated nonbank subsidiaries	$ 1,800,000,000	$ 0
Securities gains (losses), net	18,000,000	(82,000,000)	$ (7,000,000)
Total Income	9,760,000,000	6,587,000,000	5,211,000,000
Expenses
Interest	3,933,000,000	978,000,000	441,000,000
Other	184,000,000	145,000,000	148,000,000
Applicable income tax benefit	639,000,000	647,000,000	747,000,000
Net Income	2,349,000,000	2,446,000,000	2,770,000,000
Other Comprehensive Income	623,000,000	(6,317,000,000)	(1,394,000,000)
Parent Company
Income
Dividends from consolidated nonbank subsidiaries	1,819,000,000	165,000,000	3,040,000,000
Securities gains (losses), net	4,000,000	(9,000,000)	1,000,000
Interest	63,000,000	11,000,000	11,000,000
Total Income	1,886,000,000	167,000,000	3,052,000,000
Expenses
Interest	525,000,000	311,000,000	250,000,000
Other	39,000,000	19,000,000	30,000,000
Total expenses	564,000,000	330,000,000	280,000,000
Income (Loss) Before Income Taxes and Equity in Undistributed Earnings of Subsidiaries	1,322,000,000	(163,000,000)	2,772,000,000
Applicable income tax benefit	(112,000,000)	(76,000,000)	(62,000,000)
Income (Loss) Before Equity in Undistributed Earnings of Subsidiaries	1,434,000,000	(87,000,000)	2,834,000,000
Equity in undistributed earnings	915,000,000	2,533,000,000	(64,000,000)
Net Income	2,349,000,000	2,446,000,000	2,770,000,000
Other Comprehensive Income	0	0	0
Comprehensive Income Attributable to Bancorp	2,349,000,000	2,446,000,000	2,770,000,000
Dividends from Bancorp's banking subsidiary to the Bancorp's non-bank subsidiary	$ 1,800,000,000	$ 0	$ 3,000,000,000