Investment Securities - Contractual Maturities and Weighted-Average Yields of Securities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Securities available for sale
Due in 1 year or less	$ 884
Due after 1 year through 5 years	9,035
Due after 5 years through 10 years	4,764
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	67,242
Securities available for sale	81,925	$ 76,919
Amortized cost of securities available for sale
Due in 1 year or less	889
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	9,255
Due after 5 years through 10 years	5,194
Due > 10 Years	75,447
Amortized Cost	$ 90,785	87,047
Weighted average yield for securities available for sale
Due in 1 Year or Less	3.46%
Due > 1 Year through 5 Years	3.49%
Due > 5 Years through 10 Years	2.97%
Due > 10 Years	2.80%
Total weighted average yield	2.88%
U.S. Treasury securities
Securities available for sale
Due in 1 year or less	$ 217
Due after 1 year through 5 years	4,946
Due after 5 years through 10 years	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	0
Securities available for sale	5,163	5,041
Amortized cost of securities available for sale
Amortized Cost	5,230	5,129
RMBS, Agency
Securities available for sale
Due in 1 year or less	0
Due after 1 year through 5 years	91
Due after 5 years through 10 years	1,146
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	64,384
Securities available for sale	65,621	61,852
Amortized cost of securities available for sale
Amortized Cost	73,853	71,212
RMBS, Non-agency
Securities available for sale
Due in 1 year or less	0
Due after 1 year through 5 years	0
Due after 5 years through 10 years	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	730
Securities available for sale	730	737
Amortized cost of securities available for sale
Amortized Cost	641	653
RMBS
Securities available for sale
Due in 1 year or less	0
Due after 1 year through 5 years	91
Due after 5 years through 10 years	1,146
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	65,114
Securities available for sale	66,351	62,589
Amortized cost of securities available for sale
Amortized Cost	$ 74,494	71,865
Weighted average yield for securities available for sale
Weighted-average expected life	6 years 10 months 24 days
CMBS, Agency
Securities available for sale
Due in 1 year or less	$ 180
Due after 1 year through 5 years	2,533
Due after 5 years through 10 years	3,588
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	2,128
Securities available for sale	8,429	7,870
Amortized cost of securities available for sale
Amortized Cost	$ 9,076	8,626
Weighted average yield for securities available for sale
Weighted-average expected life	4 years 9 months 18 days
Other securities
Securities available for sale
Due in 1 year or less	$ 487
Due after 1 year through 5 years	1,465
Due after 5 years through 10 years	30
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	0
Securities available for sale	1,982	1,419
Amortized cost of securities available for sale
Amortized Cost	$ 1,985	$ 1,427

Available-for-sale Securities, Expected Debt Maturities, Amortized Cost Basis, Rolling Maturity

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Available-for-sale Securities, Expected Debt Maturities, Fair Value, Rolling Maturity [Abstract]

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amortized cost excluding accrued interest, before allowance for credit loss, of 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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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Amount excluding accrued interest, of 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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Weighted average yield of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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