Debt (Long-term Debt Schedule) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Total long-term debt	$ 17,762	$ 17,029
Subordinated debt	1,000	1,000
Secured debt	10,124	7,619
Long-term debt, due within one year	4,418	5,869
Long-term debt, due after one year	13,344	11,160
Derivative contracts in a payable position		62
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Derivative contracts in a payable position	2,500
Unsecured debt
Debt Instrument [Line Items]
Fixed rate	9,929	9,297
Hedge basis adjustments	108	113
Total long-term debt	$ 10,037	$ 9,410
Weighted average stated interest rate	5.08%	4.87%
Long-term debt, due within one year	$ 2,023	$ 1,028
Long-term debt, due after one year	$ 8,014	$ 8,382
Unsecured debt | Minimum
Debt Instrument [Line Items]
Interest rate	0.60%	0.60%
Unsecured debt | Maximum
Debt Instrument [Line Items]
Interest rate	8.00%	8.00%
Secured debt
Debt Instrument [Line Items]
Fixed rate	$ 7,603	$ 7,502
Hedge basis adjustments	4	(3)
Variable rate	118	120
Total long-term debt	$ 7,725	$ 7,619
Weighted average stated interest rate	2.71%	2.14%
Variable interest entity debt	$ 2,400	$ 1,300
Long-term debt, due within one year	2,395	4,841
Long-term debt, due after one year	$ 5,330	$ 2,778
Secured debt | Minimum
Debt Instrument [Line Items]
Interest rate	0.72%	0.72%
Secured debt | Maximum
Debt Instrument [Line Items]
Interest rate	5.29%	6.86%
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Secured debt	$ 5,300	$ 6,300