Deposits (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Deposits By Type [Line Items]
Noninterest-bearing deposits	$ 47,258	$ 45,695
Interest-bearing deposits	103,242	103,429
Total deposits	150,500	149,124
Interest checking
Deposits By Type [Line Items]
Interest-bearing deposits	25,915	25,410
Money market and savings
Deposits By Type [Line Items]
Interest-bearing deposits	60,349	60,461
Time deposits
Deposits By Type [Line Items]
Interest-bearing deposits	16,978	17,558
Time deposits $100,000 and greater	7,494	7,562
Time deposits $250,000 and greater	$ 3,759	$ 3,497