Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Expenses [Abstract]
Professional services	$ 364	$ 321	$ 357
Sales advertising public relations	77	114	115
Regulatory fees and assessments	61	73	91
Securities processing	41	75	52
Donations	20	51	12
Bank operations	18	43	70
Insurance	14	19	18
Other	370	566	461
Total other expenses	$ 965	$ 1,262	$ 1,176