Investment Securities - Summary of Investment Securities (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2023	Dec. 31, 2022
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	$ 7,782
Debt securities, available-for-sale	7,782	$ 9,060
Equity securities:
Equity securities, Fair Value	14	14
Marketable securities amortized cost	8,712	9,933
Marketable securities gross unrealized gain	12	14
Marketable securities gross unrealized loss	928	873
Total securities	7,796	9,074
Interest receivable	32	31
Agency - commercial
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	5,488	5,242
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	7
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	532	460
Debt securities, available-for-sale	4,960	4,789
Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	3,208	4,675
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	8	7
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	394	411
Debt securities, available-for-sale	2,822	4,271
Mortgage Backed Securities And Other Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	8,696	9,917
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	12	14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	926	871
Debt securities, available-for-sale	7,782	9,060
Equity Securities
Equity securities:
Equity securities, Amortized Cost	16	16
Equity securities, Gross Unrealized Loss	2	2
Equity securities, Fair Value	14	14
GSE certificates \| Agency - commercial
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	1,366	1,457
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	162	160
Debt securities, available-for-sale	1,204	1,297
GSE CMOs \| Agency - commercial
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	3,942	3,600
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	369	300
Debt securities, available-for-sale	3,573	3,301
Private Label CMOs \| Agency - commercial
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	180	185
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	0
Debt securities, available-for-sale	183	191
U. S. Treasury obligations \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	0	1,491
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	4
Debt securities, available-for-sale	0	1,487
GSE debentures \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	1,974	1,749
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	330	351
Debt securities, available-for-sale	1,644	1,398
Asset-backed securities \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	332	375
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	9	14
Debt securities, available-for-sale	323	361
Municipal bonds \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	7	30
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale	7	30
Corporate bonds \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	789	913
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	3	2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	39	30
Debt securities, available-for-sale	753	885
Foreign notes \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	10	20
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2	0
Debt securities, available-for-sale	8	20
Capital trust notes \| Debt Securities
Debt securities available-for-sale
Debt securities, available-for-sale, amortized cost, total	96	97
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	5	5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	14	12
Debt securities, available-for-sale	87	90
Mutual funds and common stock \| Equity Securities
Equity securities:
Equity securities, Amortized Cost	16	16
Equity securities, Gross Unrealized Loss	2	2
Equity securities, Fair Value	$ 14	$ 14

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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