Loans and Allowance for Loan Losses Loans and Allowance for Loan Losses (Details 15) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Loans disclosures
Transfers of loans from held for investment to held for sale, net	$ (126)	$ 260	$ (356)	$ (179)
Proceeds from sale	299	115	646	164
Commercial portfolio
Loans disclosures
Transfers of loans from held for investment to held for sale, net	126	260	360	179
Proceeds from sale	299	115	646	164
Consumer portfolio
Loans disclosures
Transfers of loans from held for investment to held for sale, net	0	0	(4)	0
Proceeds from sale	$ 0	$ 0	$ 0	$ 0