Long-Term Debt - Notes Associated with Consolidated VIEs (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Debt Instrument
Principal amount		$ 1,370
Long-term debt	[1]	14,973	$ 14,970
Debt, outstanding note		14,500	$ 14,600
Variable Interest Entity, Primary Beneficiary | Automobile Loans
Debt Instrument
Carrying value of loan leases or lines of credits securitized		1,430
Long-term debt		543
Debt, outstanding note		80
Subsidiaries
Debt Instrument
Long-term debt		7,212
Subsidiaries | Automobile Loans
Debt Instrument
Long-term debt reatined		$ 68

[1] Includes $55 and $74 of other short-term investments, $756 and $1,354 of portfolio loans and leases, $(7) and $(7) of ALLL, $5 and $8 of other assets, $2 and $2 of other liabilities and $656 and $1,253 of long-term debt from consolidated VIEs that are included in their respective captions above at December 31, 2020 and 2019, respectively. For further information, refer to Note 13.