Investments HTM Major Security Types) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	$ 9	$ 6
Gross Unrealized Losses	(4)	(9)
Held-to-Maturity Securities, Fair Value	452	757
Held-to-maturity securities (fair value of $452 and $757)	447	760
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	8	6
Gross Unrealized Losses	0	(2)
Held-to-Maturity Securities, Fair Value	132	362
Held-to-maturity securities (fair value of $452 and $757)	124	358
State or Local Housing Agency Obligations [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Held-to-Maturity Securities, Fair Value	22	29
Held-to-maturity securities (fair value of $452 and $757)	21	29
Non-Mortgage-Backed Securities [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	9	6
Gross Unrealized Losses	0	(2)
Held-to-Maturity Securities, Fair Value	154	391
Held-to-maturity securities (fair value of $452 and $757)	145	387
U.S. Obligations MBS [Member] | Single Family [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Held-to-Maturity Securities, Fair Value	1	2
Held-to-maturity securities (fair value of $452 and $757)	1	2
GSE MBS [Member] | Single Family [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4)	(7)
Held-to-Maturity Securities, Fair Value	295	362
Held-to-maturity securities (fair value of $452 and $757)	299	369
Private-Label MBS [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Held-to-Maturity Securities, Fair Value	2	2
Held-to-maturity securities (fair value of $452 and $757)	2	2
Mortgage-Backed Securities [Member]
Schedule of Held-to-Maturity Securities [Line Items]
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4)	(7)
Held-to-Maturity Securities, Fair Value	298	366
Held-to-maturity securities (fair value of $452 and $757)	$ 302	$ 373