Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 161	$ 240
Derivative Liability, Fair Value, Gross Liability	112	29
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(154)	(160)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	(45)	(26)
Derivative Liability, Not Subject to Master Netting Arrangement	2	0
Derivative assets, net	7	80
Derivative liabilities, net	69	3
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	7	80
Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	7	3
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	62	0
Debt Securities, Trading, Restricted	1,613	1,390
Over the Counter [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	159	159
Derivative Liability, Fair Value, Gross Liability	47	27
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(152)	(158)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	(42)	(24)
Derivative Liability, Not Subject to Master Netting Arrangement	2	0
Derivative assets, net	7	1
Derivative liabilities, net	7	3
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	7	1
Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	7	3
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, Fair Value, Gross Asset	2	81
Derivative Liability, Fair Value, Gross Liability	65	2
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(2)	(2)
Derivative Asset, Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	(3)	(2)
Derivative Liability, Not Subject to Master Netting Arrangement	0	0
Derivative assets, net	0	79
Derivative liabilities, net	62	0
Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	0	79
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	62	0
Additional Net Excess Exposure Collateral Pledged to Counterparties
Offsetting Assets and Liabilities [Line Items]
Debt Securities, Trading, Restricted	$ 1,600	$ 1,400