Investment Securities - Contractual Maturities and Weighted-Average Yields of Securities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Dec. 31, 2024
Fair value of securities available for sale:
Due in 1 Year or Less	$ 4,305
Due > 1 Year through 5 Years	6,908
Due > 5 Years through 10 Years	5,782
Due > 10 Years	67,367
Total	84,362	$ 83,013
Amortized cost of securities available for sale
Due in 1 Year or Less	4,312
Due > 1 Year through 5 Years	7,013
Due > 5 Years through 10 Years	6,050
Due > 10 Years	75,552
Total	$ 92,927	92,995
Weighted-average yield for securities available for sale
Due in 1 Year or Less	4.26%
Due > 1 Year through 5 Years	4.10%
Due > 5 Years through 10 Years	3.73%
Due > 10 Years	3.42%
Total	3.53%
U.S. Treasury securities
Fair value of securities available for sale:
Due in 1 Year or Less	$ 3,242
Due > 1 Year through 5 Years	920
Due > 5 Years through 10 Years	2,059
Due > 10 Years	0
Total	6,221	6,110
Amortized cost of securities available for sale
Total	6,222	6,114
RMBS, Agency
Fair value of securities available for sale:
Due in 1 Year or Less	1
Due > 1 Year through 5 Years	67
Due > 5 Years through 10 Years	1,107
Due > 10 Years	64,820
Total	65,995	64,707
Amortized cost of securities available for sale
Total	74,163	74,177
RMBS, Non-agency
Fair value of securities available for sale:
Due in 1 Year or Less	0
Due > 1 Year through 5 Years	0
Due > 5 Years through 10 Years	22
Due > 10 Years	599
Total	621	621
Amortized cost of securities available for sale
Total	557	567
Total RMBS
Fair value of securities available for sale:
Due in 1 Year or Less	1
Due > 1 Year through 5 Years	67
Due > 5 Years through 10 Years	1,129
Due > 10 Years	65,419
Total	66,616	65,328
Amortized cost of securities available for sale
Total	$ 74,720	74,744
Weighted-average yield for securities available for sale
Weighted-average expected life	7 years 8 months 12 days
Agency CMBS
Fair value of securities available for sale:
Due in 1 Year or Less	$ 898
Due > 1 Year through 5 Years	2,554
Due > 5 Years through 10 Years	2,574
Due > 10 Years	1,948
Total	7,974	7,825
Amortized cost of securities available for sale
Total	$ 8,437	8,389
Weighted-average yield for securities available for sale
Weighted-average expected life	4 years 7 months 6 days
Other securities
Fair value of securities available for sale:
Due in 1 Year or Less	$ 164
Due > 1 Year through 5 Years	3,367
Due > 5 Years through 10 Years	20
Due > 10 Years	0
Total	3,551	3,750
Amortized cost of securities available for sale
Total	$ 3,548	$ 3,748

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

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