Sales of Receivables and Servicing Rights - Changes in the Servicing Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of period			$ 656	$ 993
Servicing rights originated			172	150
Servicing rights purchased			210	36
Changes in fair value: Due to changes in inputs or assumptions	$ 20	$ 4	123	(340)
Changes in fair value: Other changes in fair value			(218)	(179)
Balance, end of period	$ 943	$ 660	$ 943	$ 660