Investment Securities - Summary of Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt securities available-for-sale
Amortized Cost	$ 10,402
Fair Value	10,402	$ 9,145
Equity securities with readily determinable fair values:
Fair Value	14	14
Total Securities
Amortized Cost	11,311	9,958
Gross Unrealized Gain	39	62
Gross Unrealized Loss	934	861
Fair Value	10,416	9,159
Amortized cost of investment securities	3
Interest receivable	$ 35	$ 38
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Mortgage Backed Securities And Other Securities
Debt securities available-for-sale
Amortized Cost	$ 11,295	$ 9,942
Gross Unrealized Gain	39	62
Gross Unrealized Loss	932	859
Fair Value	10,402	9,145
Mortgage- Related Securities
Debt securities available-for-sale
Amortized Cost	9,155	7,035
Gross Unrealized Gain	33	56
Gross Unrealized Loss	615	528
Fair Value	8,573	6,563
GSE certificates
Debt securities available-for-sale
Amortized Cost	1,273	1,366
Gross Unrealized Gain	0	1
Gross Unrealized Loss	167	146
Fair Value	1,106	1,221
GSE CMOs
Debt securities available-for-sale
Amortized Cost	7,724	5,495
Gross Unrealized Gain	27	48
Gross Unrealized Loss	447	381
Fair Value	7,304	5,162
Private label collateralized mortgage obligations
Debt securities available-for-sale
Amortized Cost	158	174
Gross Unrealized Gain	6	7
Gross Unrealized Loss	1	1
Fair Value	163	180
Debt Securities
Debt securities available-for-sale
Amortized Cost	2,140	2,907
Gross Unrealized Gain	6	6
Gross Unrealized Loss	317	331
Fair Value	1,829	2,582
U. S. Treasury obligations
Debt securities available-for-sale
Amortized Cost		198
Gross Unrealized Gain		0
Gross Unrealized Loss		0
Fair Value		198
GSE debentures
Debt securities available-for-sale
Amortized Cost	1,502	1,899
Gross Unrealized Gain	0	1
Gross Unrealized Loss	299	291
Fair Value	1,203	1,609
Asset-backed securities
Debt securities available-for-sale
Amortized Cost	237	307
Gross Unrealized Gain	1	0
Gross Unrealized Loss	2	5
Fair Value	236	302
Municipal bonds
Debt securities available-for-sale
Amortized Cost	5	6
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	5	6
Corporate bonds
Debt securities available-for-sale
Amortized Cost	314	365
Gross Unrealized Gain	0	0
Gross Unrealized Loss	6	22
Fair Value	308	343
Foreign notes
Debt securities available-for-sale
Amortized Cost	35	35
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	1
Fair Value	35	34
Capital trust notes
Debt securities available-for-sale
Amortized Cost	47	97
Gross Unrealized Gain	5	5
Gross Unrealized Loss	10	12
Fair Value	42	90
Equity Securities
Equity securities with readily determinable fair values:
Amortized Cost	16
Gross Unrealized Loss	2
Fair Value	14
Mutual funds
Equity securities with readily determinable fair values:
Amortized Cost	16	16
Gross Unrealized Loss	2	2
Fair Value	$ 14	$ 14

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