Investment Securities - Contractual Maturities and Weighted-Average Yields of Securities (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2024	Dec. 31, 2023
Fair value of securities available for sale:
Due in 1 Year or Less	$ 4,806
Due > 1 Year through 5 Years	6,100
Due > 5 Years through 10 Years	5,065
Due > 10 Years	63,279
Total	79,250	$ 79,117
Amortized cost of securities available for sale
Due in 1 Year or Less	4,825
Due > 1 Year through 5 Years	6,277
Due > 5 Years through 10 Years	5,441
Due > 10 Years	73,011
Total	$ 89,554	88,063
Weighted-average yield for securities available for sale
Due in 1 Year or Less	4.44%
Due > 1 Year through 5 Years	4.19%
Due > 5 Years through 10 Years	3.77%
Due > 10 Years	3.18%
Total	3.36%
U.S. Treasury securities
Fair value of securities available for sale:
Due in 1 Year or Less	$ 4,004
Due > 1 Year through 5 Years	1,128
Due > 5 Years through 10 Years	897
Due > 10 Years	0
Total	6,029	5,282
Amortized cost of securities available for sale
Total	6,053	5,330
RMBS, Agency
Fair value of securities available for sale:
Due in 1 Year or Less	2
Due > 1 Year through 5 Years	79
Due > 5 Years through 10 Years	1,058
Due > 10 Years	60,677
Total	61,816	62,948
Amortized cost of securities available for sale
Total	71,516	71,294
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	8
Due > 10 Years	650
Total	658	690
Amortized cost of securities available for sale
Total	589	610
Total RMBS
Fair value of securities available for sale:
Due in 1 Year or Less	2
Due > 1 Year through 5 Years	79
Due > 5 Years through 10 Years	1,066
Due > 10 Years	61,327
Total	62,474	63,638
Amortized cost of securities available for sale
Total	$ 72,105	71,904
Weighted-average yield for securities available for sale
Weighted-average expected life	7 years 10 months 24 days
Agency CMBS
Fair value of securities available for sale:
Due in 1 Year or Less	$ 523
Due > 1 Year through 5 Years	2,643
Due > 5 Years through 10 Years	3,082
Due > 10 Years	1,952
Total	8,200	8,323
Amortized cost of securities available for sale
Total	$ 8,853	8,961
Weighted-average yield for securities available for sale
Weighted-average expected life	4 years 2 months 12 days
Other securities
Fair value of securities available for sale:
Due in 1 Year or Less	$ 277
Due > 1 Year through 5 Years	2,250
Due > 5 Years through 10 Years	20
Due > 10 Years	0
Total	2,547	1,874
Amortized cost of securities available for sale
Total	$ 2,543	$ 1,868

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

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