Investments (Details) - Table - AFS Securities (Amortized Cost & Fair Values) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
AFS Securities
Amortized Cost	$ 19,704	$ 20,144
Allowance for Credit Losses	(44)	(32)
Gross Unrealized Gains	170	158
Gross Unrealized Losses	(28)	(17)
Estimated Fair Value	19,802	20,253
U.S. Treasury obligations
AFS Securities
Amortized Cost	6,302	6,384
Allowance for Credit Losses	0	0
Gross Unrealized Gains	10	9
Gross Unrealized Losses	0	0
Estimated Fair Value	6,312	6,393
State housing agency obligations:
AFS Securities
Amortized Cost	67	42
Allowance for Credit Losses	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	0
Estimated Fair Value	64	42
MBS - GSEs
AFS Securities
Amortized Cost	12,502	12,819
Allowance for Credit Losses	0	0
Gross Unrealized Gains	138	118
Gross Unrealized Losses	(1)	0
Estimated Fair Value	12,639	12,937
PLRMBS
AFS Securities
Amortized Cost	833	899
Allowance for Credit Losses	(44)	(32)
Gross Unrealized Gains	22	31
Gross Unrealized Losses	(24)	(17)
Estimated Fair Value	787	881
MBS
AFS Securities
Amortized Cost	13,335	13,718
Allowance for Credit Losses	(44)	(32)
Gross Unrealized Gains	160	149
Gross Unrealized Losses	(25)	(17)
Estimated Fair Value	$ 13,426	$ 13,818

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