Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Expenses [Abstract]
Insurance	$ 118	$ 93	$ 126
Regulatory fees and assessments	106	82	115
Bank operations	80	62	105
Sales advertising public relations	67	52	65
Litigation	(15)	50	422
Other	233	245	185
Total other expenses	$ 589	$ 584	$ 1,018