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Investment Securities - Investment Available for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 97,656	$ 92,995
Allowance for Credit Losses	(3)	(4)
Gross Unrealized Gains	486	148
Gross Unrealized Losses	(7,088)	(10,126)
Fair Value	91,051	83,013
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	9,958	6,114
Allowance for Credit Losses	0	0
Gross Unrealized Gains	55	5
Gross Unrealized Losses	0	(9)
Fair Value	10,013	6,110
RMBS, Agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	75,561	74,177
Allowance for Credit Losses	0	0
Gross Unrealized Gains	322	57
Gross Unrealized Losses	(6,742)	(9,527)
Fair Value	69,141	64,707
RMBS, Non-agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	525	567
Allowance for Credit Losses	(3)	(4)
Gross Unrealized Gains	67	64
Gross Unrealized Losses	(2)	(6)
Fair Value	587	621
Total RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	76,086	74,744
Allowance for Credit Losses	(3)	(4)
Gross Unrealized Gains	389	121
Gross Unrealized Losses	(6,744)	(9,533)
Fair Value	69,728	65,328
Agency CMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	8,201	8,389
Allowance for Credit Losses	0	0
Gross Unrealized Gains	35	17
Gross Unrealized Losses	(344)	(581)
Fair Value	7,892	7,825
Other securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	3,411	3,748
Allowance for Credit Losses	0	0
Gross Unrealized Gains	7	5
Gross Unrealized Losses	0	(3)
Fair Value	3,418	3,750
Asset-backed Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 1,900	$ 2,000

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