Contingencies (Details 2) $ in Millions	Dec. 31, 2018 USD ($)
Franchise Lending Program Guarantees
Loss Contingencies [Line Items]
Loss contingency, amount of guarantee	$ 26
Total loans outstanding	50
Guarantee of Indebtedness of Others
Loss Contingencies [Line Items]
Loss contingency, amount of guarantee	10
Guarantee of Indebtedness of Others | Franchise Loan Pool Guarantees [Member]
Loss Contingencies [Line Items]
Loss contingency, amount of guarantee	2
Total loans outstanding	$ 9