Debt Under Vehicle Programs and Borrowing Arrangements (Narrative) (Details) $ in Millions	1 Months Ended	9 Months Ended
	Sep. 30, 2025 USD ($) agreement	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Debt Instrument [Line Items]
Number of repurchase agreements | agreement	2
Debt under vehicle programs	$ 19,262	$ 19,262	$ 17,536
Repurchase Facility
Debt Instrument [Line Items]
Debt interest, tenor period		1 month
Debt under vehicle programs	112	$ 112
Interest rate		6.16%
Securities pledged as collateral	273	$ 273
Second Repurchase Facility
Debt Instrument [Line Items]
Debt under vehicle programs	$ 66	$ 66
Interest rate		5.10%