Debt - Schedule of Long-term Debt Portfolio (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total long-term debt	$ 17,495	$ 17,570
Subordinated debt	2,000	1,500
Secured debt	8,058	10,443
Unsecured debt
Debt Instrument [Line Items]
Fixed rate	10,974	10,327
Hedge basis adjustments	88	97
Total long-term debt	$ 11,062	$ 10,424
Weighted average stated interest rate	6.25%	6.03%
Unsecured debt | Minimum
Debt Instrument [Line Items]
Interest rate	1.15%	0.60%
Unsecured debt | Maximum
Debt Instrument [Line Items]
Interest rate	8.00%	8.00%
Secured debt
Debt Instrument [Line Items]
Fixed rate	$ 6,358	$ 7,031
Hedge basis adjustments		2
Variable rate	75	113
Total long-term debt	$ 6,433	$ 7,146
Weighted average stated interest rate	4.32%	3.31%
Variable interest entity debt	$ 1,600	$ 1,500
Secured debt | Minimum
Debt Instrument [Line Items]
Interest rate	1.96%	0.89%
Secured debt | Maximum
Debt Instrument [Line Items]
Interest rate	12.75%	5.29%
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Secured debt	$ 4,200	$ 5,600