Debt - Schedule of Long-term Debt (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-term debt, due within one year	$ 3,740	$ 4,340
Long-term debt, due after one year	13,067	13,230
Long-term debt	16,807	17,570
Secured debt	8,558	10,443
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	1,289	1,409
Long-term debt, due after one year	8,731	9,015
Long-term debt	10,020	10,424
Secured debt
Debt Instrument [Line Items]
Long-term debt, due within one year	2,451	2,931
Long-term debt, due after one year	4,336	4,215
Long-term debt	6,787	7,146
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Secured debt	$ 4,800	$ 5,600