Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Other Expenses [Abstract]
Professional services	$ 75	$ 91	$ 155	$ 172
Regulatory fees and assessments	19	17	37	29
Sales advertising public relations	16	12	33	30
Securities processing	2	15	14	30
Insurance	3	3	6	8
Bank operations	2	4	4	13
Other	82	101	172	191
Total other expenses	$ 199	$ 243	$ 421	$ 473