Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Expenses [Abstract]
Professional services	$ 91	$ 89	$ 246	$ 261
Regulatory fees and assessments	16	16	53	45
Sales advertising public relations	13	20	46	50
Securities processing	8	10	22	40
Insurance	3	2	9	10
Bank operations	3	2	7	15
Other	87	90	259	281
Total other expenses	$ 221	$ 229	$ 642	$ 702