Loans and Allowance for Loan Losses - Loans in Consumer Portfolio Segment and Purchased Credit Impaired Loans Segment (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Consumer portfolio loans
Nonaccrual	$ 689	$ 552
Total	77,314	78,921
Consumer
Consumer portfolio loans
Accrual	33,131	30,370
Nonaccrual	197	225
Total	33,328	30,595
Consumer | Residential mortgage
Consumer portfolio loans
Accrual	29,665	27,154
Nonaccrual	171	190
Total	29,836	27,344
Consumer | Home equity and other consumer loans
Consumer portfolio loans
Accrual	3,466	3,216
Nonaccrual	26	35
Total	3,492	3,251
Purchased Credit- Impaired
Consumer portfolio loans
Nonaccrual	4	6
Purchased Credit- Impaired | Consumer
Consumer portfolio loans
Accrual	105	148
Nonaccrual	0	0
Total	105	148
Consumer and Purchased Credit Impaired Loans
Consumer portfolio loans
Accrual	33,236	30,518
Nonaccrual	197	225
Total	$ 33,433	$ 30,743