Investment Securities - Summary of Unrealized Loss Positions on Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	$ 1,674	$ 2,357
Less than Twelve Months, Unrealized Loss	3	84
Twelve Months or Longer, Fair Value	5,606	4,198
Twelve Months or Longer, Unrealized Loss	931	777
Fair Value	7,280	6,555
Unrealized Loss	934	861
Debt Securities | U.S. Government and GSE Obligations
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	181
Less than Twelve Months, Unrealized Loss	0	1
Twelve Months or Longer, Fair Value	1,203	1,362
Twelve Months or Longer, Unrealized Loss	299	290
Fair Value	1,203	1,543
Unrealized Loss	299	291
Debt Securities | GSE certificates
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	38	312
Less than Twelve Months, Unrealized Loss	0	5
Twelve Months or Longer, Fair Value	1,040	843
Twelve Months or Longer, Unrealized Loss	167	141
Fair Value	1,078	1,155
Unrealized Loss	167	146
Debt Securities | Private Label collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	29
Less than Twelve Months, Unrealized Loss	0	1
Twelve Months or Longer, Fair Value	17	0
Twelve Months or Longer, Unrealized Loss	1	0
Fair Value	17	29
Unrealized Loss	1	1
Debt Securities | GSE CMOs
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	1,636	1,835
Less than Twelve Months, Unrealized Loss	3	77
Twelve Months or Longer, Fair Value	2,822	1,312
Twelve Months or Longer, Unrealized Loss	444	304
Fair Value	4,458	3,147
Unrealized Loss	447	381
Debt Securities | Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	154	228
Twelve Months or Longer, Unrealized Loss	2	5
Fair Value	154	228
Unrealized Loss	2	5
Debt Securities | Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	5	6
Twelve Months or Longer, Unrealized Loss	0	0
Fair Value	5	6
Unrealized Loss	0	0
Debt Securities | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	308	343
Twelve Months or Longer, Unrealized Loss	6	22
Fair Value	308	343
Unrealized Loss	6	22
Debt Securities | Foreign notes
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	10	9
Twelve Months or Longer, Unrealized Loss	0	1
Fair Value	10	9
Unrealized Loss	0	1
Debt Securities | Capital trust notes
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	33	81
Twelve Months or Longer, Unrealized Loss	10	12
Fair Value	33	81
Unrealized Loss	10	12
Equity Securities
Debt Securities, Available-for-sale [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than Twelve Months, Unrealized Loss	0	0
Twelve Months or Longer, Fair Value	14	14
Twelve Months or Longer, Unrealized Loss	2	2
Fair Value	14	14
Unrealized Loss	$ 2	$ 2