Variable Interest Entities - Loans Sold to Third-Party Sponsored Securitization Entities (Details) - Nonconsolidated entities - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Summary of loan sale activities
Carrying value of loans sold	$ 24,459	$ 17,447	$ 47,606	$ 42,382
Proceeds received from loan sales as cash	24	13	40	22
Proceeds from loans sales as securities	24,033	17,274	46,782	41,937
Total proceeds received from loan sales	24,057	17,287	46,822	41,959
Gains/(losses) on loan sales	$ 0	$ 2	$ 4	$ 6