Derivatives and Hedging Activities (Derivatives in Statement of Condition) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 186,162	$ 155,094
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	240	202
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	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 assets, net	80	804
Derivative liabilities, net	3	6
Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset	137	159
Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset	3	815
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	162,769	99,170
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	237	200
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	29	60
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	23,393	55,924
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	3	2
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	23,176	55,732
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	3	1
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	111	91
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	1
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Mortgage Receivable [Member] | Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	106	101
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ 0	$ 0