Derivatives (Estimated Fair Value of Derivative Assets and Liabilities after Master Netting Agreements and Cash Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset Excluding Accruals	$ 8,370	$ 8,918
Derivative Liability, Fair Value, Gross Liability Excluding Accruals	7,272	6,307
Net amount of derivative assets after application of master netting agreements and cash collateral	53	183
Net amount of derivative liabilities after application of master netting agreements and cash collateral	9	19
Over the Counter [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset Excluding Accruals	8,224	8,749
Derivative Liability, Fair Value, Gross Liability Excluding Accruals	6,966	6,014
Derivative Asset, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	(3,633)	(3,568)
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	(3,633)	(3,568)
Cash collateral on derivative assets	(2,597)	(3,448)
Cash collateral on derivative liabilities	0	0
Securities collateral on derivative assets	(1,955)	(1,563)
Securities collateral on derivative liabilities	(3,325)	(2,427)
Cleared [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset Excluding Accruals	135	158
Derivative Liability, Fair Value, Gross Liability Excluding Accruals	299	277
Derivative Asset, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	(5)	(5)
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	(5)	(5)
Cash collateral on derivative assets	(126)	(150)
Cash collateral on derivative liabilities	(289)	(239)
Securities collateral on derivative assets	0	0
Securities collateral on derivative liabilities	(4)	(33)
Exchange Traded [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset Excluding Accruals	11	11
Derivative Liability, Fair Value, Gross Liability Excluding Accruals	7	16
Gross estimated fair value of derivative assets	1	1
Gross estimated fair value of derivative liabilities	1	1
Cash collateral on derivative assets	0	0
Cash collateral on derivative liabilities	(6)	(5)
Securities collateral on derivative assets	0	0
Securities collateral on derivative liabilities	$ 0	$ (10)