Borrowed Funds - Breakdown of Borrowed Funds (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt Instrument
Total borrowed funds	$ 14,178	$ 14,426
Total wholesale borrowings
Debt Instrument
Total borrowed funds	13,150	13,400
FHLB advances
Debt Instrument
Total borrowed funds	13,150	13,400
Federal Reserve Bank term funding
Debt Instrument
Total borrowed funds	0	0
Junior subordinated debentures
Debt Instrument
Total borrowed funds	583	582
Subordinated notes
Debt Instrument
Total borrowed funds	$ 445	$ 444