Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	$ 240	$ 202
Derivative Liability, Subject to Master Netting Arrangement, before Offset	29	60
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(160)	602
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(26)	(54)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Not Subject to Master Netting Arrangement	0	0
Derivative Asset	80	804
Derivative Liability	3	6
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	80	804
Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	3	6
Debt Securities, Trading, Restricted	1,390	533
Derivative, Collateral, Obligation to Return Securities That Can Be Sold or Repledged	0	0
Derivative, Collateral, Right to Reclaim Securities That Can Be Sold or Repledged	0	0
Over-the-Counter [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	159	181
Derivative Liability, Subject to Master Netting Arrangement, before Offset	27	57
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(158)	(180)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(24)	(51)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Not Subject to Master Netting Arrangement	0	0
Derivative Asset	1	1
Derivative Liability	3	6
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	1	1
Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	3	6
Derivative, Collateral, Obligation to Return Securities That Can Be Sold or Repledged	0	0
Derivative, Collateral, Right to Reclaim Securities That Can Be Sold or Repledged	0	0
Exchange Cleared [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	81	21
Derivative Liability, Subject to Master Netting Arrangement, before Offset	2	3
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(2)	782
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(2)	(3)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Not Subject to Master Netting Arrangement	0	0
Derivative Asset	79	803
Derivative Liability	0	0
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	79	803
Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	0	0
Derivative, Collateral, Obligation to Return Securities That Can Be Sold or Repledged	0	0
Derivative, Collateral, Right to Reclaim Securities That Can Be Sold or Repledged	$ 0	$ 0