Derivatives and Hedging Activities (Derivatives in Statement of Income and Impact on Interest) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Net gain/(loss) on derivatives	$ (15)	$ 15
Total net gain/(loss) related to derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(14)	16
Not Designated as Hedging Instrument, Economic Hedge \| Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(24)	11
Not Designated as Hedging Instrument, Economic Hedge \| Net interest settlements
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	10	5
Not Designated as Hedging Instrument \| Price Alignment Amount
Derivative Instruments, Gain (Loss) [Line Items]
Price Alignment Amount	$ (1)	$ (1)

Derivative Instruments Not Designated as Hedging Instruments, After Price Alignment, Gain (Loss), Net

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- Definition

Other net gain (loss) on derivative instruments recognized in earnings during the period.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4E

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4C

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4CC
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4CC

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