Investment Securities - Contractual Maturities and Weighted-Average Yields of Securities (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2022	Dec. 31, 2021
Securities available for sale
Due in 1 year or less	$ 4,399
Due after 1 year through 5 years	7,569
Due after 5 years through 10 years	5,031
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	66,023
Securities available for sale	83,022	$ 95,261
Amortized cost of securities available for sale
Due in 1 year or less	4,399
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	7,705
Due after 5 years through 10 years	5,365
Due > 10 Years	72,464
Amortized Cost	$ 89,933
Weighted average yield for securities available for sale
Due in 1 Year or Less	0.83%
Due > 1 Year through 5 Years	1.27%
Due > 5 Years through 10 Years	2.02%
Due > 10 Years	2.09%
Total weighted average yield	1.95%
U.S. Treasury securities
Securities available for sale
Due in 1 year or less	$ 3,893
Due after 1 year through 5 years	4,731
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	8,624	9,442
RMBS, Agency
Securities available for sale
Due in 1 year or less	0
Due after 1 year through 5 years	106
Due after 5 years through 10 years	1,100
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	63,499
Securities available for sale	64,705	72,620
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	822
Securities available for sale	822	996
RMBS
Securities available for sale
Due in 1 year or less	0
Due after 1 year through 5 years	106
Due after 5 years through 10 years	1,100
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	64,321
Securities available for sale	$ 65,527	73,616
Weighted average yield for securities available for sale
Weighted-average expected life	6 years 8 months 12 days
CMBS, Agency
Securities available for sale
Due in 1 year or less	$ 285
Due after 1 year through 5 years	1,897
Due after 5 years through 10 years	3,690
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	1,702
Securities available for sale	$ 7,574	9,369
Weighted average yield for securities available for sale
Weighted-average expected life	5 years 4 months 24 days
Other securities
Securities available for sale
Due in 1 year or less	$ 221
Due after 1 year through 5 years	835
Due after 5 years through 10 years	241
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	0
Securities available for sale	$ 1,297	$ 2,834

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

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Debt Maturities, Available-for-Sale, Weighted Average Expected Life

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Amortized cost 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
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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