Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other Expenses [Abstract]
Insurance	$ 21	$ 28	$ 44	$ 65
Regulatory fees and assessments	18	25	38	58
Securities processing	6	14	10	34
Litigation	0	253	0	403
Other	93	83	158	144
Total other expenses	$ 138	$ 403	$ 250	$ 704